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Author name code: cauzzi
ADS astronomy entries on 2022-09-14
author:"Cauzzi, Gianna" 

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Title: Development of Integral Field Spectrographs to Revolutionize
    Spectroscopic Observations of Solar Flares and other Energetic
    Solar Eruptions
Authors: Lin, Haosheng; Anan, Tetsu; Cauzzi, Gianna; Fletcher, Lyndsay;
   Huang, Pei; Kowalski, Adam; Kramar, Maxim; Qiu, Jiong; Samra, Jenna;
   Spittler, Constance; Sukegawa, Takashi; Wirth, Gregory
2022arXiv220900788L    Altcode:
  The Sun's proximity offers us a unique opportunity to study in detail
  the physical processes on a star's surface; however, the highly dynamic
  nature of the stellar surface -- in particular, energetic eruptions
  such as flares and coronal mass ejections -- presents tremendous
  observational challenges. Spectroscopy probes the physical state of
  the solar atmosphere, but conventional scanning spectrographs and
  spectrometers are unable to capture the full evolutionary history of
  these dynamic events with a sufficiently wide field of view and high
  spatial, spectral, and temporal resolution. Resolving the physics of the
  dynamic sun requires gathering simultaneous spectra across a contiguous
  area over the full duration of these events, a goal now tantalizingly
  close to achievable with continued investment in developing powerful
  new Integral Field Spectrographs to serve as the foundation of both
  future ground- and space-based missions. This technology promises to
  revolutionize our ability to study solar flares and CMEs, addressing
  NASA's strategic objective to "understand the Sun, solar system, and
  universe." Since such events generate electromagnetic radiation and
  high-energy particles that disrupt terrestrial electric infrastructure,
  this investment not only advances humanity's scientific endeavors
  but also enhances our space weather forecasting capability to protect
  against threats to our technology-reliant civilization.

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Title: IBIS-A: The IBIS data Archive. High-resolution observations
    of the solar photosphere and chromosphere with contextual data
Authors: Ermolli, Ilaria; Giorgi, Fabrizio; Murabito, Mariarita;
   Stangalini, Marco; Guido, Vincenzo; Molinaro, Marco; Romano, Paolo;
   Guglielmino, Salvatore L.; Viavattene, Giorgio; Cauzzi, Gianna;
   Criscuoli, Serena; Reardon, Kevin P.; Tritschler, Alexandra
2022A&A...661A..74E    Altcode: 2022arXiv220209946E
  Context. The IBIS data Archive (IBIS-A) stores data acquired with
  the Interferometric BIdimensional Spectropolarimeter (IBIS), which
  was operated at the Dunn Solar Telescope of the US National Solar
  Observatory from June 2003 to June 2019. The instrument provided series
  of high-resolution narrowband spectropolarimetric imaging observations
  of the photosphere and chromosphere in the range 5800-8600 Å and
  co-temporal broadband observations in the same spectral range and
  with the same field of view as for the polarimetric data. <BR />
  Aims: We present the data currently stored in IBIS-A, as well as the
  interface utilized to explore such data and facilitate its scientific
  exploitation. To this end, we also describe the use of IBIS-A data
  in recent and undergoing studies relevant to solar physics and
  space weather research. <BR /> Methods: IBIS-A includes raw and
  calibrated observations, as well as science-ready data. The latter
  comprise maps of the circular, linear, and net circular polarization,
  and of the magnetic and velocity fields derived for a significant
  fraction of the series available in the archive. IBIS-A furthermore
  contains links to observations complementary to the IBIS data, such
  as co-temporal high-resolution observations of the solar atmosphere
  available from the instruments onboard the Hinode and IRIS satellites,
  and full-disk multi-band images from INAF solar telescopes. <BR />
  Results: IBIS-A currently consists of 30 TB of data taken with IBIS
  during 28 observing campaigns performed in 2008 and from 2012 to 2019
  on 159 days. Of the observations, 29% are released as Level 1 data
  calibrated for instrumental response and compensated for residual seeing
  degradation, while 10% of the calibrated data are also available as
  Level 1.5 format as multi-dimensional arrays of circular, linear, and
  net circular polarization maps, and line-of-sight velocity patterns;
  81% of the photospheric calibrated series present Level 2 data with
  the view of the magnetic and velocity fields of the targets, as derived
  from data inversion with the Very Fast Inversion of the Stokes Vector
  code. Metadata and movies of each calibrated and science-ready series
  are also available to help users evaluate observing conditions. <BR />
  Conclusions: IBIS-A represents a unique resource for investigating
  the plasma processes in the solar atmosphere and the solar origin of
  space weather events. The archive currently contains 454 different
  series of observations. A recently undertaken effort to preserve
  IBIS observations is expected to lead in the future to an increase in
  the raw measurements and the fraction of processed data available in
  IBIS-A. <P />Research supported by the H2020 SOLARNET grant no. 824135.

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Title: Subarcsecond Imaging of a Solar Active Region Filament With
    ALMA and IRIS
Authors: da Silva Santos, J. M.; White, S. M.; Reardon, K.; Cauzzi,
   G.; Gunár, S.; Heinzel, P.; Leenaarts, J.
2022FrASS...9.8115D    Altcode: 2022arXiv220413178D
  Quiescent filaments appear as absorption features on the solar disk
  when observed in chromospheric lines and at continuum wavelengths
  in the millimeter (mm) range. Active region (AR) filaments are their
  small-scale, low-altitude analogues, but they could not be resolved
  in previous mm observations. This spectral diagnostic can provide
  insight into the details of the formation and physical properties of
  their fine threads, which are still not fully understood. Here, we shed
  light on the thermal structure of an AR filament using high-resolution
  brightness temperature (Tb) maps taken with ALMA Band 6 complemented by
  simultaneous IRIS near-UV spectra, Hinode/SOT photospheric magnetograms,
  and SDO/AIA extreme-UV images. Some of the dark threads visible in the
  AIA 304 Å passband and in the core of Mg ii resonance lines have dark
  (Tb &lt; 5,000 K) counterparts in the 1.25 mm maps, but their visibility
  significantly varies across the filament spine and in time. These
  opacity changes are possibly related to variations in temperature and
  electron density in filament fine structures. The coolest Tb values
  (&lt; 5,000 K) coincide with regions of low integrated intensity in the
  Mg ii h and k lines. ALMA Band 3 maps taken after the Band 6 ones do not
  clearly show the filament structure, contrary to the expectation that
  the contrast should increase at longer wavelengths based on previous
  observations of quiescent filaments. The ALMA maps are not consistent
  with isothermal conditions, but the temporal evolution of the filament
  may partly account for this.

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Title: A Prototype of a Large Tunable Fabry-Pérot Interferometer
    for Solar Spectroscopy
Authors: Greco, V.; Sordini, A.; Cauzzi, G.; Cavallini, F.; Del
   Vecchio, C.; Giovannelli, L.; Berrilli, F.; Del Moro, D.; Reardon,
   K.; Pietraszewski, K. A. R. B.
2022PASP..134a5007G    Altcode: 2021arXiv211202224G
  Large Fabry-Pérot Interferometers (FPIs) are used in a variety of
  astronomical instrumentation, including spectro-polarimeters for 4 m
  class solar telescopes. In this work we comprehensively characterize
  the cavity of a prototype 150 mm FPI, sporting a novel, fully symmetric
  design. Of particular interest, we define a new method to properly
  assess the gravity effects on the interferometer's cavity when the
  system is used in either the vertical or horizontal configuration,
  both typical of solar observations. We show that the symmetric design
  very effectively limits the combined effects of pre-load and gravity
  forces to only a few nm over a 120 mm diameter illuminated surface,
  with gravity contributing ~2 nm peak-to-valley (~0.3 nm rms) in either
  configuration. We confirm a variation of the tilt between the plates
  of the interferometer during the spectral scan, which can be mitigated
  with appropriate corrections to the spacing commands. Finally, we show
  that the dynamical response of the new system fully satisfies typical
  operational scenarios. We conclude that large, fully symmetric FPIs
  can be safely used within solar instrumentation in both, horizontal
  and vertical position, with the latter better suited to limiting the
  overall volume occupied by such an instrument.

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Title: The National Science Foundation's Daniel K. Inouye Solar
    Telescope — Status Update
Authors: Rimmele, T.; Woeger, F.; Tritschler, A.; Casini, R.; de Wijn,
   A.; Fehlmann, A.; Harrington, D.; Jaeggli, S.; Anan, T.; Beck, C.;
   Cauzzi, G.; Schad, T.; Criscuoli, S.; Davey, A.; Lin, H.; Kuhn, J.;
   Rast, M.; Goode, P.; Knoelker, M.; Rosner, R.; von der Luehe, O.;
   Mathioudakis, M.; Dkist Team
2021AAS...23810601R    Altcode:
  The National Science Foundation's 4m Daniel K. Inouye Solar Telescope
  (DKIST) on Haleakala, Maui is now the largest solar telescope in the
  world. DKIST's superb resolution and polarimetric sensitivity will
  enable astronomers to unravel many of the mysteries the Sun presents,
  including the origin of solar magnetism, the mechanisms of coronal
  heating and drivers of flares and coronal mass ejections. Five
  instruments, four of which provide highly sensitive measurements
  of solar magnetic fields, including the illusive magnetic field of
  the faint solar corona. The DKIST instruments will produce large and
  complex data sets, which will be distributed through the NSO/DKIST Data
  Center. DKIST has achieved first engineering solar light in December
  of 2019. Due to COVID the start of the operations commissioning phase
  is delayed and is now expected for fall of 2021. We present a status
  update for the construction effort and progress with the operations
  commissioning phase.

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Title: Critical Science Plan for the Daniel K. Inouye Solar Telescope
    (DKIST)
Authors: Rast, Mark P.; Bello González, Nazaret; Bellot Rubio,
   Luis; Cao, Wenda; Cauzzi, Gianna; Deluca, Edward; de Pontieu, Bart;
   Fletcher, Lyndsay; Gibson, Sarah E.; Judge, Philip G.; Katsukawa,
   Yukio; Kazachenko, Maria D.; Khomenko, Elena; Landi, Enrico; Martínez
   Pillet, Valentín; Petrie, Gordon J. D.; Qiu, Jiong; Rachmeler,
   Laurel A.; Rempel, Matthias; Schmidt, Wolfgang; Scullion, Eamon; Sun,
   Xudong; Welsch, Brian T.; Andretta, Vincenzo; Antolin, Patrick; Ayres,
   Thomas R.; Balasubramaniam, K. S.; Ballai, Istvan; Berger, Thomas E.;
   Bradshaw, Stephen J.; Campbell, Ryan J.; Carlsson, Mats; Casini,
   Roberto; Centeno, Rebecca; Cranmer, Steven R.; Criscuoli, Serena;
   Deforest, Craig; Deng, Yuanyong; Erdélyi, Robertus; Fedun, Viktor;
   Fischer, Catherine E.; González Manrique, Sergio J.; Hahn, Michael;
   Harra, Louise; Henriques, Vasco M. J.; Hurlburt, Neal E.; Jaeggli,
   Sarah; Jafarzadeh, Shahin; Jain, Rekha; Jefferies, Stuart M.; Keys,
   Peter H.; Kowalski, Adam F.; Kuckein, Christoph; Kuhn, Jeffrey R.;
   Kuridze, David; Liu, Jiajia; Liu, Wei; Longcope, Dana; Mathioudakis,
   Mihalis; McAteer, R. T. James; McIntosh, Scott W.; McKenzie, David
   E.; Miralles, Mari Paz; Morton, Richard J.; Muglach, Karin; Nelson,
   Chris J.; Panesar, Navdeep K.; Parenti, Susanna; Parnell, Clare E.;
   Poduval, Bala; Reardon, Kevin P.; Reep, Jeffrey W.; Schad, Thomas A.;
   Schmit, Donald; Sharma, Rahul; Socas-Navarro, Hector; Srivastava,
   Abhishek K.; Sterling, Alphonse C.; Suematsu, Yoshinori; Tarr, Lucas
   A.; Tiwari, Sanjiv; Tritschler, Alexandra; Verth, Gary; Vourlidas,
   Angelos; Wang, Haimin; Wang, Yi-Ming; NSO and DKIST Project; DKIST
   Instrument Scientists; DKIST Science Working Group; DKIST Critical
   Science Plan Community
2021SoPh..296...70R    Altcode: 2020arXiv200808203R
  The National Science Foundation's Daniel K. Inouye Solar Telescope
  (DKIST) will revolutionize our ability to measure, understand,
  and model the basic physical processes that control the structure
  and dynamics of the Sun and its atmosphere. The first-light DKIST
  images, released publicly on 29 January 2020, only hint at the
  extraordinary capabilities that will accompany full commissioning of
  the five facility instruments. With this Critical Science Plan (CSP)
  we attempt to anticipate some of what those capabilities will enable,
  providing a snapshot of some of the scientific pursuits that the DKIST
  hopes to engage as start-of-operations nears. The work builds on the
  combined contributions of the DKIST Science Working Group (SWG) and
  CSP Community members, who generously shared their experiences, plans,
  knowledge, and dreams. Discussion is primarily focused on those issues
  to which DKIST will uniquely contribute.

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Title: Measuring Decay Timescales of Downflows in Solar Flare
Footpoints: Testing the One-minute Theory (Abstract)
Authors: Beltzer-Sweeney, A. K.; Butler, E.; Kowalski, A.; Cauzzi, G.
2020JAVSO..48R.107B    Altcode:
  (Abstract only) In 1989 George Fisher found analytically that
  chromospheric downflows in flare footprints should slow down to
  background detection levels within ~ 1 minute regardless of the initial
  energy injected. We set to test this theory by measuring downflows in
  flare kernels that were observed by the IRIS satellite between 2014
  and 2017. The GOES classification system was used as a proxy for
  the energy of the nonthermal electron beam that is thought to heat
  the flare footprint. The redshift evolution of a Mg II triplet line
  was measured in twenty-six C, M, and X class flares to determine the
  timescale of deceleration of the chromospheric plasma in response to
  explosive flare heating. Two different methods for measuring the decay
  of the redshift as a function of time, bisector and gaussian, were
  used to test the robustness of the inferred downflow gas velocities
  across the wide variety of flares. Results of the analysis show
  that downflow velocities reached 30 ~ 50 km/s, which is consistent
  with previous results with a derived Mach number of 4 ~ 5. The times
  of half-maximum velocity were found to be between 15 ~ 30 seconds,
  indicating a rapid slowing. At later times, the Mg II line profiles
  exhibit prolonged redshifts with inferred speeds of 5 to 7 km/s.

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Title: Spectral Signatures of Chromospheric Condensation in a Major
    Solar Flare
Authors: Graham, David R.; Cauzzi, Gianna; Zangrilli, Luca; Kowalski,
   Adam; Simões, Paulo; Allred, Joel
2020ApJ...895....6G    Altcode: 2020arXiv200405075G
  We study the evolution of chromospheric line and continuum emission
  during the impulsive phase of the X-class SOL2014-09-10T17:45
  solar flare. We extend previous analyses of this flare to multiple
  chromospheric lines of Fe I, Fe II, Mg II, C I, and Si II observed
  with the Interface Region Imaging Spectrograph, combined with
  radiative-hydrodynamical (RHD) modeling. For multiple flaring kernels,
  the lines all show a rapidly evolving double-component structure: an
  enhanced emission component at rest, and a broad, highly redshifted
  component of comparable intensity. The redshifted components migrate
  from 25 to 50 km s<SUP>-1</SUP> toward the rest wavelength within ∼30
  s. Using Fermi hard X-ray observations, we derive the parameters of
  an accelerated electron beam impacting the dense chromosphere, using
  them to drive an RHD simulation with the RADYN code. As in Kowalski
  et al. (2017), our simulations show that the most energetic electrons
  penetrate into the deep chromosphere, heating it to T ∼ 10,000 K,
  while the bulk of the electrons dissipate their energy higher, driving
  an explosive evaporation, and its counterpart condensation—a very
  dense (n<SUB>e</SUB> ∼ 2 × 10<SUP>14</SUP> cm<SUP>-3</SUP>), thin
  layer (30-40 km thickness), heated to 8-12,000 K, moving toward the
  stationary chromosphere at up to 50 km s<SUP>-1</SUP>. The synthetic
  Fe II 2814.45 Å profiles closely resemble the observational
  data, including a continuum enhancement, and both a stationary
  and a highly redshifted component, rapidly moving toward the rest
  wavelength. Importantly, the absolute continuum intensity, ratio
  of component intensities, relative time of appearance, and redshift
  amplitude are sensitive to the model input parameters, showing great
  potential as diagnostics.

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Title: Solar physics in the 2020s: DKIST, parker solar probe, and
    solar orbiter as a multi-messenger constellation
Authors: Martinez Pillet, V.; Tritschler, A.; Harra, L.; Andretta, V.;
   Vourlidas, A.; Raouafi, N.; Alterman, B. L.; Bellot Rubio, L.; Cauzzi,
   G.; Cranmer, S. R.; Gibson, S.; Habbal, S.; Ko, Y. K.; Lepri, S. T.;
   Linker, J.; Malaspina, D. M.; Matthews, S.; Parenti, S.; Petrie, G.;
   Spadaro, D.; Ugarte-Urra, I.; Warren, H.; Winslow, R.
2020arXiv200408632M    Altcode:
  The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope
  (DKIST) is about to start operations at the summit of Haleakala
  (Hawaii). DKIST will join the early science phases of the NASA
  and ESA Parker Solar Probe and Solar Orbiter encounter missions. By
  combining in-situ measurements of the near-sun plasma environment and
  detail remote observations of multiple layers of the Sun, the three
  observatories form an unprecedented multi-messenger constellation to
  study the magnetic connectivity inside the solar system. This white
  paper outlines the synergistic science that this multi-messenger
  suite enables.

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Title: Measuring Decay Timescales of Downflows in Solar Flare
Footpoints: Testing the 1-minute Theory
Authors: Beltzer-Sweeney, A. K.; Butler, E.; Kowalski, A. F.;
   Cauzzi, G.
2019AGUFMSH13D3423B    Altcode:
  In 1989 George Fisher found analytically that chromospheric downflows in
  flare footprints should slow down to background detection levels within
  ~1 minute regardless of the initial energy injected. <P />We set to test
  this theory by measuring downflows in flare kernels that were observed
  by the IRIS satellite between 2014-2017. The GOES classification system
  was used as a proxy for the energy of the nonthermal electron beam
  that is thought to heat the flare footprint. The redshift evolution
  of a Mg II triplet line was measured in twenty-six C, M, and X class
  flares to determine the timescale of deceleration of the chromospheric
  plasma in response to explosive flare heating. Two different methods
  for measuring the decay of the redshift as a function of time, bisector
  and gaussian, were used to test the robustness of the inferred downflow
  gas velocities across the wide variety of flares. <P />Results of the
  analysis show that downflow velocities reached 30~50 km/s, which is
  consistent with previous results with a derived Mach number of 4~5. The
  times of half-maximum velocity were found to be between 15~30 seconds,
  indicating a rapid slowing. At later times, the Mg II line profiles
  exhibit prolonged redshifts with inferred speeds of 5-7 km/s.

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Title: IBIS-A: The IBIS Solar Spectro-polarimetric Data Archive
Authors: Ermolli, Ilaria; Giordano, Silvio; Giorgi, Fabrizio; Guido,
   Vincenzo; Marassi, Alessandro; Volpicelli, Antonio; Di Marcantonio,
   Paolo; Zuccarello, Francesca; Cauzzi, Gianna
2019ASPC..521..431E    Altcode:
  We review the efforts undertaken to set up the archive of the IBIS
  ground-based solar spectro-polarimetric observations into the VO
  framework, according to the SOLARNET standards, by using SOAP/XML and
  RESTful Web Services.

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Title: Solar Chromospheric Temperature Diagnostics: A Joint ALMA-Hα
    Analysis
Authors: Molnar, Momchil E.; Reardon, Kevin P.; Chai, Yi; Gary, Dale;
   Uitenbroek, Han; Cauzzi, Gianna; Cranmer, Steven R.
2019ApJ...881...99M    Altcode: 2019arXiv190608896M
  We present the first high-resolution, simultaneous observations of
  the solar chromosphere in the optical and millimeter wavelength
  ranges, obtained with the Atacama Large Millimeter Array (ALMA)
  and the Interferometric Bidimensional Spectrometer at the Dunn Solar
  Telescope. In this paper we concentrate on the comparison between the
  brightness temperature observed in ALMA Band 3 (3 mm; 100 GHz) and the
  core width of the Hα 6563 Å line, previously identified as a possible
  diagnostic of the chromospheric temperature. We find that in the area
  of plage, network and fibrils covered by our field of view, the two
  diagnostics are well correlated, with similar spatial structures
  observed in both. The strength of the correlation is remarkable,
  given that the source function of the millimeter radiation obeys local
  thermodynamic equilibrium, while the Hα line has a source function that
  deviates significantly from the local Planck function. The observed
  range of ALMA brightness temperatures is sensibly smaller than the
  temperature range that was previously invoked to explain the observed
  width variations in Hα. We employ analysis from forward modeling
  with the Rybicki-Hummer (RH) code to argue that the strong correlation
  between Hα width and ALMA brightness temperature is caused by their
  shared dependence on the population number n <SUB>2</SUB> of the first
  excited level of hydrogen. This population number drives millimeter
  opacity through hydrogen ionization via the Balmer continuum, and
  Hα width through a curve-of-growth-like opacity effect. Ultimately,
  the n <SUB>2</SUB> population is regulated by the enhancement or lack
  of downward Lyα flux, which coherently shifts the formation height
  of both diagnostics to regions with different temperature, respectively.

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Title: New technique to measure the cavity defects of Fabry-Perot
    interferometers
Authors: Greco, V.; Sordini, A.; Cauzzi, G.; Reardon, K.; Cavallini, F.
2019A&A...626A..43G    Altcode: 2019arXiv190501393G
  Context. Several astronomical instruments, for both nighttime and
  solar use, rely on tunable Fabry-Perot interferometers (FPIs). Knowing
  the exact shape of the etalons' cavity is crucial for assessing the
  overall instrumental transmission profile and its possible variations
  during the tuning process. <BR /> Aims: We aim to define and test
  a technique to accurately measure the cavity defects of air-spaced
  FPIs, including distortions due to the spectral tuning process that
  are typical of astronomical observations. We further aim to develop a
  correction technique to maintain the shape of the cavity as constant as
  possible during the spectral scan. These are necessary steps to optimize
  the spectral transmission profile of a two-dimensional spectrograph
  (polarimeter) using one or more FPIs in series, and to ensure that
  the spectral transmission profile remains constant during typical
  observing conditions. <BR /> Methods: We devised a generalization of the
  techniques developed for the so-called phase-shifting interferometry to
  the case of FPI. This measuring technique is applicable to any given FPI
  that can be tuned via changing the cavity spacing (z-axis), and can be
  used for any etalon regardless of the coating' reflectivity. The major
  strength of our method is the ability to fully characterize the cavity
  during a spectral scan, allowing for the determination of scan-dependent
  modifications of the plates. We have applied the measuring technique to
  three 50 mm diameter interferometers, with cavity gaps ranging between
  600 μm and 3 mm, coated for use in the visible range. <BR /> Results:
  The technique developed in this paper allows us to accurately and
  reliably measure the cavity defects of air-spaced FPIs, and of their
  evolution during the entire spectral scan. Our main, and unexpected,
  result is that the relative tilt between the two FPI plates varies
  significantly during the spectral scan, and can dominate the cavity
  defects; in particular, we observe that the tilt component at the
  extremes of the scan is sensibly larger than that at the center of
  the scan. Exploiting the capability of the electronic controllers to
  set the reference plane at any given spectral step, we then develop
  a correction technique that allows the minimization of the tilt
  during a complete spectral scan. The correction remains highly stable
  over long periods, well beyond the typical duration of astronomical
  observations. <P />Movies attached to Figs. 6 and 13 are available at <A
  href="https://www.aanda.org/10.1051/0004-6361/201935302/olm">https://www.aanda.org</A>

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Title: Spectral Evidence for Heating at Large Column Mass in Umbral
    Solar Flare Kernels. I. IRIS Near-UV Spectra of the X1 Solar Flare
    of 2014 October 25
Authors: Kowalski, Adam F.; Butler, Elizabeth; Daw, Adrian N.;
   Fletcher, Lyndsay; Allred, Joel C.; De Pontieu, Bart; Kerr, Graham S.;
   Cauzzi, Gianna
2019ApJ...878..135K    Altcode: 2019arXiv190502111K
  The GOES X1 flare SOL2014-10-25T17:08:00 was a three-ribbon solar
  flare observed with the Interface Region Imaging Spectrograph (IRIS)
  in the near-UV (NUV) and far-UV. One of the flare ribbons crossed
  a sunspot umbra, producing a dramatic, ∼1000% increase in the NUV
  continuum radiation. We comprehensively analyze the UV spectral data
  of the umbral flare brightenings, which provide new challenges for
  radiative-hydrodynamic modeling of the chromospheric velocity field and
  the white-light continuum radiation. The emission line profiles in the
  umbral flare brightenings exhibit redshifts and profile asymmetries,
  but these are significantly smaller than in another, well-studied
  X-class solar flare. We present a ratio of the NUV continuum intensity
  to the Fe II λ2814.45 intensity. This continuum-to-line ratio is a
  new spectral diagnostic of significant heating at high column mass
  (log m/[g cm<SUP>-2</SUP>] &gt; -2) during solar flares because the
  continuum and emission line radiation originate from relatively similar
  temperatures but moderately different optical depths. The full spectral
  readout of these IRIS data also allow for a comprehensive survey of the
  flaring NUV landscape: in addition to many lines of Fe II and Cr II, we
  identify a new solar flare emission line, He I λ2829.91 (as previously
  identified in laboratory and early-type stellar spectra). The Fermi/GBM
  hard X-ray data provide inputs to radiative-hydrodynamic models (which
  will be presented in Paper II) in order to better understand the large
  continuum-to-line ratios, the origin of the white-light continuum
  radiation, and the role of electron beam heating in the low atmosphere.

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Title: High Resolution Observations of Chromospheric Condensation
Authors: Cauzzi, Gianna; Graham, David; Zangrilli, Luca; Kowalski, Adam
2019shin.confE.180C    Altcode:
  The chromospheric response to flaring can provide information on
  the coronal magnetic reconnection processes driving the flare. In
  particular, the evolution of the chromospheric condensation can
  trace the site and size of episodes of energy release in the corona,
  and inform on their duration. High resolution, spectrally resolved
  observations of chromospheric lines and continua are necessary to fully
  study this phenomenon. <P />High cadence observations of chromospheric
  condensation in small flaring kernels, derived from a multi-spectral
  analysis of IRIS UV lines in a well-studied X1 flare, put some hard
  constraints on these values. In particular, it is found that the
  chromospheric signatures occurr sequentially in multiple distinct
  positions, separated by only 0.3"

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Title: The Critical Science Plan for DKIST
Authors: Rast, M.; Cauzzi, G.; Martinez Pillet, V.
2019NCimC..42....7R    Altcode:
  The 4-meter Daniel K. Inouye Solar Telescope is nearing completion on
  Haleakala, Maui, with first light expected in 2020. In preparation
  for early science, the National Solar Observatory is reaching out
  to the solar community in order to define the critical science goals
  for the first two years of DKIST operations. The overall aim of this
  "Critical Science Plan" is to be ready, by start of operations, to
  execute a set of observations that take full advantage of the DKIST
  capabilities to address critical compelling science.

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Title: IRIS Ultraviolet Spectral Properties of a Sample of X-Class
    Solar Flares
Authors: Butler, Elizabeth; Kowalski, Adam; Cauzzi, Gianna; Allred,
   Joel C.; Daw, Adrian N.
2018AAS...23212101B    Altcode:
  The white-light (near-ultraviolet (NUV) and optical) continuum emission
  comprises the majority of the radiated energy in solar flares. However,
  there are nearly as many explanations for the origin of the white-light
  continuum radiation as there are white-light flares that have been
  studied in detail with spectra. Furthermore, there are rarely robust
  constraints on the time-resolved dynamics in the white-light emitting
  flare layers. We are conducting a statistical study of the properties of
  Fe II lines, Mg II lines, and NUV continuum intensity in bright flare
  kernels observed by the Interface Region Imaging Spectrograph (IRIS),
  in order to provide comprehensive constraints for radiative-hydrodynamic
  flare models. Here we present a new technique for identifying bright
  flare kernels and preliminary relationships among IRIS spectral
  properties for a sample of X-class solar flares.

---------------------------------------------------------
Title: Hα and Hβ emission in a C3.3 solar flare: comparison between
    observations and simulations
Authors: Zuccarello, F.; Simoes, P. J. D. A.; Capparelli, V.; Fletcher,
   L.; Romano, P.; Mathioudakis, M.; Cauzzi, G.; Carlsson, M.; Kuridze,
   D.; Keys, P.
2017AGUFMSH41A2742Z    Altcode:
  This work is based on the analysis of an extremely rare set of
  simultaneous observations of a C3.3 solar flare in the Hα and Hβ lines
  at high spatial and temporal resolution, which were acquired at the
  Dunn Solar Telescope. Images of the C3.3 flare (SOL2014-04-22T15:22)
  made at various wavelengths along the Hα line profile by the
  Interferometric Bidimensional Spectrometer (IBIS) and in the Hβ
  with the Rapid Oscillations in the Solar Atmosphere (ROSA) broadband
  imager are analyzed to obtain the intensity evolution. The analysis
  shows that Hα and Hβ intensity excesses in three identified flare
  footpoints are well correlated in time. In the stronger footpoints,
  the typical value of the the Hα/Hβ intensity ratio observed is ∼
  0.4 - 0.5, in broad agreement with values obtained from a RADYN non-LTE
  simulation driven by an electron beam with parameters constrained by
  observations. The weaker footpoint has a larger Hα/Hβ ratio, again
  consistent with a RADYN simulation but with a smaller energy flux.

---------------------------------------------------------
Title: Hα and Hβ Emission in a C3.3 Solar Flare: Comparison between
    Observations and Simulations
Authors: Capparelli, Vincenzo; Zuccarello, Francesca; Romano, Paolo;
   Simões, Paulo J. A.; Fletcher, Lyndsay; Kuridze, David; Mathioudakis,
   Mihalis; Keys, Peter H.; Cauzzi, Gianna; Carlsson, Mats
2017ApJ...850...36C    Altcode: 2017arXiv171004067C
  The hydrogen Balmer series is a basic radiative loss channel from
  the flaring solar chromosphere. We report here on the analysis of an
  extremely rare set of simultaneous observations of a solar flare in the
  {{H}}α and {{H}}β lines, at high spatial and temporal resolutions,
  that were acquired at the Dunn Solar Telescope. Images of the C3.3 flare
  (SOL2014-04-22T15:22) made at various wavelengths along the {{H}}α line
  profile by the Interferometric Bidimensional Spectrometer (IBIS) and in
  the {{H}}β with the Rapid Oscillations in the Solar Atmosphere (ROSA)
  broadband imager are analyzed to obtain the intensity evolution. The
  {{H}}α and {{H}}β intensity excesses in three identified flare
  footpoints are well-correlated in time. We examine the ratio of {{H}}α
  to {{H}}β flare excess, which was proposed by previous authors as
  a possible diagnostic of the level of electron-beam energy input. In
  the stronger footpoints, the typical value of the the {{H}}α /H β
  intensity ratio observed is ∼0.4-0.5, in broad agreement with values
  obtained from a RADYN non-LTE simulation driven by an electron beam
  with parameters constrained (as far as possible) by observation. The
  weaker footpoint has a larger {{H}}α /H β ratio, again consistent
  with a RADYN simulation, but with a smaller energy flux. The {{H}}α
  line profiles observed have a less prominent central reversal than is
  predicted by the RADYN results, but can be brought into agreement if
  the {{H}}α -emitting material has a filling factor of around 0.2-0.3.

---------------------------------------------------------
Title: The Atmospheric Response to High Nonthermal Electron Beam
    Fluxes in Solar Flares. I. Modeling the Brightest NUV Footpoints in
    the X1 Solar Flare of 2014 March 29
Authors: Kowalski, Adam F.; Allred, Joel C.; Daw, Adrian; Cauzzi,
   Gianna; Carlsson, Mats
2017ApJ...836...12K    Altcode: 2016arXiv160907390K
  The 2014 March 29 X1 solar flare (SOL20140329T17:48) produced bright
  continuum emission in the far- and near-ultraviolet (NUV) and highly
  asymmetric chromospheric emission lines, providing long-sought
  constraints on the heating mechanisms of the lower atmosphere in
  solar flares. We analyze the continuum and emission line data from
  the Interface Region Imaging Spectrograph (IRIS) of the brightest
  flaring magnetic footpoints in this flare. We compare the NUV spectra
  of the brightest pixels to new radiative-hydrodynamic predictions
  calculated with the RADYN code using constraints on a nonthermal
  electron beam inferred from the collisional thick-target modeling of
  hard X-ray data from Reuven Ramaty High Energy Solar Spectroscopic
  Imager. We show that the atmospheric response to a high beam flux
  density satisfactorily achieves the observed continuum brightness
  in the NUV. The NUV continuum emission in this flare is consistent
  with hydrogen (Balmer) recombination radiation that originates from
  low optical depth in a dense chromospheric condensation and from the
  stationary beam-heated layers just below the condensation. A model
  producing two flaring regions (a condensation and stationary layers)
  in the lower atmosphere is also consistent with the asymmetric Fe II
  chromospheric emission line profiles observed in the impulsive phase.

---------------------------------------------------------
Title: A Chromospheric Flare Model Consisting of Two Dynamical Layers:
    Critical Tests from IRIS Data of Solar Flares
Authors: Kowalski, Adam; Allred, Joel C.; Daw, Adrian N.; Cauzzi,
   Gianna; Carlsson, Mats; Inglis, Andrew; O'Neill, Aaron; Mathioudakis,
   Mihalis; Uitenbroek, Han
2017AAS...22933902K    Altcode:
  Recent 1D radiative-hydrodynamic simulations of flares have shown that
  a heated, chromospheric compression layer and a stationary layer, just
  below the compression, are produced in response to high flux electron
  beam heating. The hot blackbody-like continuum and redshifted intensity
  in singly ionized chromospheric lines in these model predictions are
  generally consistent with broad wavelength coverage spectra of M dwarf
  flares and with high spectral resolution observations of solar flares,
  respectively. We critically test this two-component chromospheric
  flare model against the Fe II profiles and NUV continuum brightness
  for several X-class solar flares observed with the Interface Region
  Imaging Spectrograph (IRIS). We present several new predictions for
  the Daniel K. Inoue Solar Telescope (DKIST).

---------------------------------------------------------
Title: Flares In Time-Domain Surveys
Authors: Kowalski, Adam; Hawley, Suzanne; Davenport, James; Berlicki,
   Arkadiusz; Cauzzi, Gianna; Fletcher, Lyndsay; Heinzel, Petr; Notsu,
   Yuta; Loyd, Parke; Martinez Oliveros, Juan Carlos; Pugh, Chloe;
   Schmidt, Sarah Jane; Karmakar, Subhajeet; Pye, John; Flaccomio, Ettore
2016csss.confE.126K    Altcode:
  Proceedings for the splinter session "Flares in Time-Domain Surveys"
  convened at Cool Stars 19 on June 07, 2016 in Uppsala, Sweden. Contains
  a two page summary of the splinter session, links to YouTube talks,
  and a PDF copy of the slides from the presenters.

---------------------------------------------------------
Title: Spectral analysis and modeling of solar flares chromospheric
    condensation
Authors: Cauzzi, Gianna; Graham, David; Kowalski, Adam; Zangrilli,
   Luca; Simoes, Paulo; Allred, Joel C.
2016SPD....47.0609C    Altcode:
  We follow up on our recent analysis of the X1.1 flare
  SOL2014-09-10T17:45, where we studied the impulsive phase dynamics
  of tens of individual flaring "kernels", in both coronal (Fe XXI)
  and chromospheric (MgII) lines observed at high cadence with IRIS.We
  concentrate here on the chromospheric aspect of the phenomenon,
  extending the analysis to multiple spectral lines of Mg II, Fe II,
  Si I, C II. We show that many flaring kernels display high velocity
  downflows in the spectra of all these chromospheric lines, exhibiting
  distinct, transient and strongly redshifted spectral components.From
  modeling using RADYN with the thick-target interpretation, the presence
  of two spectral components appears to be consistent with a high flux
  beam of accelerated electrons, characterized by a hard spectrum. In
  particular the highest energy electrons heat the denser, lower layers
  of the atmosphere, while the bulk of the beam energy, deposited higher
  in the atmosphere, is sufficient to produce chromospheric evaporation
  with a corresponding condensation.

---------------------------------------------------------
Title: FUV Continuum in Flare Kernels Observed by IRIS
Authors: Daw, Adrian N.; Kowalski, Adam; Allred, Joel C.; Cauzzi,
   Gianna
2016SPD....47.0604D    Altcode:
  Fits to Interface Region Imaging Spectrograph (IRIS) spectra observed
  from bright kernels during the impulsive phase of solar flares are
  providing long-sought constraints on the UV/white-light continuum
  emission. Results of fits of continua plus numerous atomic and molecular
  emission lines to IRIS far ultraviolet (FUV) spectra of bright kernels
  are presented. Constraints on beam energy and cross sectional area
  are provided by cotemporaneous RHESSI, FERMI, ROSA/DST, IRIS slit-jaw
  and SDO/AIA observations, allowing for comparison of the observed IRIS
  continuum to calculations of non-thermal electron beam heating using
  the RADYN radiative-hydrodynamic loop model.

---------------------------------------------------------
Title: Commission 12: Solar Radiation and Structure
Authors: Cauzzi, Gianna; Shchukina, Nataliya; Kosovichev, Alexander;
   Bianda, Michele; Brandenburg, Axel; Chou, Dean-Yi; Dasso, Sergio; Ding,
   Ming-De; Jefferies, Stuart; Krivova, Natalie; Kuznetsov, Vladimir D.;
   Moreno-Insertis, Fernando
2016IAUTA..29..278C    Altcode:
  Commission 12 of the International Astronomical Union encompasses
  investigations of the internal structure and dynamics of the Sun,
  the quiet solar atmosphere, solar radiation and its variability, and
  the nature of relatively stable magnetic structures like sunspots,
  faculae and the magnetic network. The Commission sees participation
  of over 300 scientists worldwide.

---------------------------------------------------------
Title: ADAHELI: exploring the fast, dynamic Sun in the x-ray, optical,
    and near-infrared
Authors: Berrilli, Francesco; Soffitta, Paolo; Velli, Marco; Sabatini,
   Paolo; Bigazzi, Alberto; Bellazzini, Ronaldo; Bellot Rubio, Luis
   Ramon; Brez, Alessandro; Carbone, Vincenzo; Cauzzi, Gianna; Cavallini,
   Fabio; Consolini, Giuseppe; Curti, Fabio; Del Moro, Dario; Di Giorgio,
   Anna Maria; Ermolli, Ilaria; Fabiani, Sergio; Faurobert, Marianne;
   Feller, Alex; Galsgaard, Klaus; Gburek, Szymon; Giannattasio, Fabio;
   Giovannelli, Luca; Hirzberger, Johann; Jefferies, Stuart M.; Madjarska,
   Maria S.; Manni, Fabio; Mazzoni, Alessandro; Muleri, Fabio; Penza,
   Valentina; Peres, Giovanni; Piazzesi, Roberto; Pieralli, Francesca;
   Pietropaolo, Ermanno; Martinez Pillet, Valentin; Pinchera, Michele;
   Reale, Fabio; Romano, Paolo; Romoli, Andrea; Romoli, Marco; Rubini,
   Alda; Rudawy, Pawel; Sandri, Paolo; Scardigli, Stefano; Spandre,
   Gloria; Solanki, Sami K.; Stangalini, Marco; Vecchio, Antonio;
   Zuccarello, Francesca
2015JATIS...1d4006B    Altcode:
  Advanced Astronomy for Heliophysics Plus (ADAHELI) is a project concept
  for a small solar and space weather mission with a budget compatible
  with an European Space Agency (ESA) S-class mission, including launch,
  and a fast development cycle. ADAHELI was submitted to the European
  Space Agency by a European-wide consortium of solar physics research
  institutes in response to the "Call for a small mission opportunity
  for a launch in 2017," of March 9, 2012. The ADAHELI project builds
  on the heritage of the former ADAHELI mission, which had successfully
  completed its phase-A study under the Italian Space Agency 2007 Small
  Mission Programme, thus proving the soundness and feasibility of
  its innovative low-budget design. ADAHELI is a solar space mission
  with two main instruments: ISODY: an imager, based on Fabry-Pérot
  interferometers, whose design is optimized to the acquisition of
  highest cadence, long-duration, multiline spectropolarimetric images
  in the visible/near-infrared region of the solar spectrum. XSPO: an
  x-ray polarimeter for solar flares in x-rays with energies in the 15
  to 35 keV range. ADAHELI is capable of performing observations that
  cannot be addressed by other currently planned solar space missions,
  due to their limited telemetry, or by ground-based facilities, due to
  the problematic effect of the terrestrial atmosphere.

---------------------------------------------------------
Title: IRIS observations of chromospheric evaporation in multiple,
    individual flaring kernels
Authors: Cauzzi, Gianna; Graham, David; Zangrilli, Luca
2015IAUGA..2257379C    Altcode:
  We present new results from IRIS showing the dynamic evolution
  of chromospheric evaporation in a flare ribbon, with the highest
  temporal and spatial resolution to date. IRIS observed the entire
  duration of an X-class event using a 9 second cadence 'sit and stare'
  mode. As the ribbon brightened successively at new positions along
  the slit, a unique impulsive phase evolution was observed for about 80
  individual spatial pixels in both coronal (Fe XXI) and chromospheric
  (MgII) lines.Each activation of a new footpoint kernel displays the
  same initial coronal up-flows of up to ~350 km/s, co-temporal and
  co-spatial with chromospheric downflows up to 40 km/s. This represents
  one of the most convincing examples of the development and evolution
  of chromospheric evaporation. Further, the temporal evolution of flows
  is remarkably similar between all slit pixel positions, leading to
  the conclusion that the time of energy deposition in any one footpoint
  is short - between 30-60 seconds - and occurs in an area of less than
  2". Surprisingly the Fe XXI flows are sustained for several minutes,
  and significant line broadening beyond the thermal width is seen,
  which we interperet here as plasma above the equilibrium formation
  temperature. To understand these observations we compare them with a
  hydrodynamic flare model.

---------------------------------------------------------
Title: Division II: Commission 12: Solar Radiation and Structure
Authors: Kosovichev, Alexander; Cauzzi, Gianna; Martinez Pillet,
   Valentin; Asplund, Martin; Brandenburg, Axel; Chou, Dean-Yi;
   Christensen-Dalsgaard, Jorgen; Gan, Weiqun; Kuznetsov, Vladimir D.;
   Rovira, Marta G.; Shchukina, Nataliya; Venkatakrishnan, P.
2015IAUTB..28..109K    Altcode:
  The President of C12, Alexander Kosovichev, presented the status of
  the Commission and its working Group(s). Primary activities included
  organization of international meetings (IAU Symposia, Special Sessions
  and Joint Discussion); review and support of proposals for IAU sponsored
  meetings; organization of working groups on the Commission topics
  to promote the international cooperation; preparation of triennial
  report on the organizational and science activities of Commission
  members. Commission 12 broadly encompasses topics of solar research
  which include studies of the Sun's internal structure, composition,
  dynamics and magnetism (through helioseismology and other techniques),
  studies of the quiet photosphere, chromosphere and corona, and also
  research of the mechanisms of solar radiation, and its variability on
  various time scales. Some overlap with topics covered by Commission
  10 Solar Activity is unavoidable, and many activities are sponsored
  jointly by these two commissions. The Commission website can be found
  at http://sun.stanford.edu/IAU-Com12/, with information about related
  IAU Symposiums and activities, and links to appropriate web sites.

---------------------------------------------------------
Title: Future observations of solar activity
Authors: Cauzzi, Gianna
2015IAUGA..2257363C    Altcode:
  Several large solar telescopes and instrumental projects are well
  underway and scheduled to completion in the next decade. Notable
  examples are the US-led 4-m ground-based DKIST, optimized for high
  resolution studies in the optical and infrared, that will see first
  light in 2019; the ESA-NASA Solar Orbiter, scheduled for launch in 2018
  on an innovative orbite which will provide close-up, high-latitude
  observations of the Sun; the Japan-led Solar-C spacecraft, with a
  large suite of complementary instruments aiming at understanding the
  magnetised solar atmosphere from bottom to top, that is currently
  being proposed jointly to JAXA, ESA and NASA.I will provide a short
  review of such facilities from the point of view of solar activity
  studies, highlighting the novel approach they will provide for solar
  flare analysis, and discuss the possibilities offered by coordinated
  operations of multiple telescopes.

---------------------------------------------------------
Title: Temporal Evolution of Multiple Evaporating Ribbon Sources in
    a Solar Flare
Authors: Graham, D. R.; Cauzzi, G.
2015ApJ...807L..22G    Altcode: 2015arXiv150603465G
  We present new results from the Interface Region Imaging Spectrograph
  (IRIS) showing the dynamic evolution of chromospheric evaporation
  and condensation in a flare ribbon, with the highest temporal
  and spatial resolution to date. IRIS observed the entire impulsive
  phase of the X-class flare SOL2014-09-10T17:45 using a 9.4 s cadence
  “sit-and-stare” mode. As the ribbon brightened successively at
  new positions along the slit, a unique impulsive phase evolution
  was observed for many tens of individual pixels in both coronal and
  chromospheric lines. Each activation of a new footpoint displays
  the same initial coronal upflows of up to ∼300 km s<SUP>-1</SUP>
  and chromospheric downflows up to 40 km s<SUP>-1</SUP>. Although the
  coronal flows can be delayed by over 1 minute with respect to those in
  the chromosphere, the temporal evolution of flows is strikingly similar
  between all pixels and consistent with predictions from hydrodynamic
  flare models. Given the large sample of independent footpoints, we
  conclude that each flaring pixel can be considered a prototypical,
  “elementary” flare kernel.

---------------------------------------------------------
Title: Science with Large Solar Telescopes: Overview of SpS 6
Authors: Cauzzi, Gianna; Tritschler, Alexandra; Deng, Yuanyong
2015HiA....16..439C    Altcode:
  With several large aperture optical and IR telescopes just coming
  on-line, or scheduled for the near future, solar physics is on the
  verge of a quantum leap in observational capabilities. An efficient
  use of such facilities will require new and innovative approaches to
  both observatory operations and data handling. <P />This two-days
  long Special Session discussed the science expected with large
  solar telescopes, and started addressing the strategies necessary
  to optimize their scientific return. Cutting edge solar science as
  derived from state-of-the-art observations and numerical simulations
  and modeling was presented, and discussions were held on the role of
  large facilities in satisfying the demanding requirements of spatial and
  temporal resolution, stray-light correction, and spectro-polarimetric
  accuracy. Building on the experience of recently commissioned
  telescopes, critical issues for the development of future facilities
  were discussed. These included operational issues peculiar to large
  telecopes as well as strategies for their best use.

---------------------------------------------------------
Title: Optical Spectral Observations of a Flickering White-light
    Kernel in a C1 Solar Flare
Authors: Kowalski, Adam F.; Cauzzi, Gianna; Fletcher, Lyndsay
2015ApJ...798..107K    Altcode: 2014arXiv1411.0770K
  We analyze optical spectra of a two-ribbon, long-duration
  C1.1 flare that occurred on 2011 August 18 within AR 11271
  (SOL2011-08-18T15:15). The impulsive phase of the flare was observed
  with a comprehensive set of space-borne and ground-based instruments,
  which provide a range of unique diagnostics of the lower flaring
  atmosphere. Here we report the detection of enhanced continuum emission,
  observed in low-resolution spectra from 3600 Å to 4550 Å acquired
  with the Horizontal Spectrograph at the Dunn Solar Telescope. A small,
  &lt;=0.”5 (10<SUP>15</SUP> cm<SUP>2</SUP>) penumbral/umbral kernel
  brightens repeatedly in the optical continuum and chromospheric
  emission lines, similar to the temporal characteristics of the hard
  X-ray variation as detected by the Gamma-ray Burst Monitor on the Fermi
  spacecraft. Radiative-hydrodynamic flare models that employ a nonthermal
  electron beam energy flux high enough to produce the optical contrast
  in our flare spectra would predict a large Balmer jump in emission,
  indicative of hydrogen recombination radiation from the upper flare
  chromosphere. However, we find no evidence of such a Balmer jump in
  the bluemost spectral region of the continuum excess. Just redward of
  the expected Balmer jump, we find evidence of a "blue continuum bump"
  in the excess emission which may be indicative of the merging of the
  higher order Balmer lines. The large number of observational constraints
  provides a springboard for modeling the blue/optical emission for this
  particular flare with radiative-hydrodynamic codes, which are necessary
  to understand the opacity effects for the continuum and emission line
  radiation at these wavelengths.

---------------------------------------------------------
Title: Continuum Emission from a Microflare Kernel Observed by IRIS
Authors: Daw, A. N.; Kowalski, A. F.; Wuelser, J. P.; Cauzzi, G.;
   Allred, J. C.; Christe, S.
2014AGUFMSH51C4166D    Altcode:
  Fits to Interface Region Imaging Spectrograph (IRIS) spectra observed
  from a bright kernel during the impulsive phase of a solar microflare
  (GOES class B9) are presented, providing long-sought constraints on
  the UV/white-light continuum emission during flares. Constraints on
  beam energy and cross sectional area are provided by cotemporaneous
  RHESSI and SDO/AIA 1700 A observations, respectively, allowing for
  comparison of the observed IRIS continuum to calculations of non-thermal
  electron beam heating using the RADYN radiative-hydrodynamic loop
  model. Implications for flare energy release are discussed.

---------------------------------------------------------
Title: Chromospheric umbral dynamics
Authors: Reardon, Kevin P.; Vecchio, Antonio; Cauzzi, Gianna;
   Tritschler, Alexandra
2014AAS...22432304R    Altcode:
  The chromosphere above sunspots is seen to undergo dynamical driving
  from perturbations from lower layers of the atmosphere. Umbral
  flashes have long been understood to be the result of acoustic shocks
  due to the drop in density in the sunspot chromosphere. Detailed
  observations of the umbral waves and flashes may help reveal the
  nature of the sunspot structure in the upper atmosphere. We report
  on high-resolution observations of umbral dynamics observed in the Ca
  II 8542 line by IBIS at the Dunn Solar Telescope. We use a principal
  component decomposition technique (POD) to isolate different components
  of the observed oscillations. We are able to explore temporal and
  spatial evolution of the umbral flashes. We find significant variation
  in the nature of the flashes over the sunspot, indicating that the
  chromospheric magnetic topology can strongly modify the nature of the
  umbral intensity and velocity oscillations.

---------------------------------------------------------
Title: F-CHROMA.Flare Chromospheres: Observations, Models and Archives
Authors: Cauzzi, Gianna; Fletcher, Lyndsay; Mathioudakis, Mihalis;
   Carlsson, Mats; Heinzel, Petr; Berlicki, Arek; Zuccarello, Francesca
2014AAS...22412339C    Altcode:
  F-CHROMA is a collaborative project newly funded under the EU-Framework
  Programme 7 "FP7-SPACE-2013-1", involving seven different European
  research Institutes and Universities. The goal of F-CHROMA is to
  substantially advance our understanding of the physics of energy
  dissipation and radiation in the flaring solar atmosphere, with a
  particular focus on the flares' chromosphere. A major outcome of the
  F-CHROMA project will be the creation of an archive of chromospheric
  flare observations and models to be made available to the community
  for further research.In this poster we describe the structure and
  milestones of the project, the different activities planned, as well
  as early results. Emphasis will be given to the dissemination efforts
  of the project to make results of these activities available to and
  usable by the community.

---------------------------------------------------------
Title: Chromospheric Diagnostics from IRIS and DST
Authors: Cauzzi, Gianna; Reardon, Kevin P.; Jaeggli, Sarah A.;
   Reid, Aaron
2014AAS...22430201C    Altcode:
  Using data obtained during a coordinated observing campaign in
  September 2013, we compare the spectral and imaging diagnostics from
  IRIS and the instruments at the Dunn Solar Telescope (DST). We focus
  on a small active region observed for approximately one hour with IRIS
  (NUV, FUV, and SJI) in conjunction with IBIS, FIRS, and ROSA from the
  DST.In particular, we examine the line widths and intensities in the
  different chromospheric lines (H-alpha, Ca II 8542, Mg II) and the
  temporal evolution of these different diagnostics. This allows us to
  better relate the views from new window provided by IRIS to previous
  studies of the chromosphere.

---------------------------------------------------------
Title: The Solar Chromosphere Observed at 1 Hz and 0.”2 Resolution
Authors: Lipartito, Isabel; Judge, Philip G.; Reardon, Kevin; Cauzzi,
   Gianna
2014ApJ...785..109L    Altcode: 2014arXiv1401.4474L
  We recently reported extremely rapid changes in chromospheric fine
  structure observed using the IBIS instrument in the red wing of
  Hα. Here, we examine data obtained during the same observing run
  (2010 August 7), of a mature active region NOAA 11094. We analyze
  more IBIS data including wavelength scans and data from the Solar
  Dynamics Observatory, all from within a 30 minute interval. Using a
  slab radiative transfer model, we investigate the physical nature of
  fibrils in terms of tube-like versus sheet-like structures. Principal
  Component Analysis shows that the very rapid Hα variations in the
  line wings depend mostly on changes of line width and line shift,
  but for Ca II 854.2 the variations are dominated by changes in column
  densities. The tube model must be rejected for a small but significant
  class of fibrils undergoing very rapid changes. If our wing data arise
  from the same structures leading to "type II spicules," our analysis
  calls into question much recent work. Instead, the data do not reject
  the hypothesis that some fibrils are optical superpositions of plasma
  collected into sheets. We review how Parker's theory of tangential
  discontinuities naturally leads to plasma collecting into sheets,
  and show that the sheet picture is falsifiable. Chromospheric fine
  structures seem to be populated by both tubes and sheets. We assess the
  merits of spectral imaging versus slit spectroscopy for future studies.

---------------------------------------------------------
Title: Comet C/2012 S1 (ISON): Observations of the Dust Grains from
    SOFIA and of the Atomic Gas from NSO Dunn and McMath-Pierce Solar
    Telescopes (Invited)
Authors: Wooden, D. H.; Woodward, C. E.; Harker, D. E.; Kelley, M. S.;
   Sitko, M.; Reach, W. T.; De Pater, I.; Gehrz, R. D.; Kolokolova,
   L.; Cochran, A. L.; McKay, A. J.; Reardon, K.; Cauzzi, G.; Tozzi,
   G.; Christian, D. J.; Jess, D. B.; Mathioudakis, M.; Lisse, C. M.;
   Morgenthaler, J. P.; Knight, M. M.
2013AGUFM.P24A..07W    Altcode:
  Comet C/2012 S1 (ISON) is unique in that it is a dynamically new comet
  derived from the Oort cloud reservoir of comets with a sun-grazing
  orbit. Infrared (IR) and visible wavelength observing campaigns were
  planned on NASA's Stratospheric Observatory For Infrared Astronomy
  (SOFIA) and on National Solar Observatory Dunn (DST) and McMath-Pierce
  Solar Telescopes, respectively. We highlight our early results. SOFIA
  (+FORCAST [1]) mid- to far-IR images and spectroscopy (~5-35 μm)
  of the dust in the coma of ISON are to be obtained by the ISON-SOFIA
  Team during a flight window 2013 Oct 21-23 UT (r_h≈1.18 AU). Dust
  characteristics, identified through the 10 μm silicate emission
  feature and its strength [2], as well as spectral features from
  cometary crystalline silicates (Forsterite) at 11.05-11.2 μm, and
  near 16, 19, 23.5, 27.5, and 33 μm are compared with other Oort cloud
  comets that span the range of small and/or highly porous grains (e.g.,
  C/1995 O1 (Hale-Bopp) [3,4,5] and C/2001 Q4 (NEAT) [6]) to large and/or
  compact grains (e.g., C/2007 N4 (Lulin) [7] and C/2006 P1 (McNaught)
  [8]). Measurement of the crystalline peaks in contrast to the broad
  10 and 20 μm amorphous silicate features yields the cometary silicate
  crystalline mass fraction [9], which is a benchmark for radial transport
  in our protoplanetary disk [10]. The central wavelength positions,
  relative intensities, and feature asymmetries for the crystalline
  peaks may constrain the shapes of the crystals [11]. Only SOFIA can
  look for cometary organics in the 5-8 μm region. Spatially resolved
  measurements of atoms and simple molecules from when comet ISON is
  near the Sun (r_h&lt; 0.4 AU, near Nov-20--Dec-03 UT) were proposed
  for by the ISON-DST Team. Comet ISON is the first comet since comet
  Ikeya-Seki (1965f) [12,13] suitable for studying the alkalai metals Na
  and K and the atoms specifically attributed to dust grains including
  Mg, Si, Fe, as well as Ca. DST's Horizontal Grating Spectrometer
  (HGS) measures 4 settings: Na I, K, C2 to sample cometary organics
  (along with Mg I), and [O I] as a proxy for activity from water [14]
  (along with Si I and Fe I). State-of-the-art instruments that will also
  be employed include IBIS [15], which is a Fabry-Perot spectral imaging
  system that concurrently measures lines of Na, K, Ca II, or Fe, and ROSA
  (CSUN/QUB) [16], which is a rapid imager that simultaneously monitors Ca
  II or CN. From McMath-Pierce, the Solar-Stellar Spectrograph also will
  target ISON (320-900 nm, R~21,000, r_h&lt;0.3 AU). Assuming survival,
  the intent is to target ISON over r_h&lt;0.4 AU, characteristic of
  prior Na detections [12,13,17,18,19]. References: [1] Adams, J.D., et
  al. 2012, SPIE, 8446, 16; [2] Kelley, M.S., Wooden, D.H. 2009, PSS, 57,
  1133; [3] Harker et al. 2002, ApJ, 580, 579; [4] Hayward et al. 2000,
  ApJ, 538, 428; [5] Hadamcik, E., Levasseur-Regourd, A.C. 2003, JQSRT,
  79-80, 661; [6] Wooden, D.H. 2004, ApJL, 612, L77; [7] Woodward et
  al. 2011, AJ, 141, 181; [8] Kelley et al. 2010, LPSC, 41, #2375;
  [9] Kelley, M.S. et al. 2011, AAS, 211, 560; [10] Wooden, D.H. 2008,
  SSRv, 138, 75; [11] Lindsay et al. 2013, ApJ, 766, 54; [12] Preston,
  G. W. 1967, ApJ, 147, 718; [13] Slaughter, C.D. 1969, AJ, 74, 929;
  [14] McKay et al. 2012, Icarus, 222, 684; [15] Cavallini, F., 2006,
  Solar Phys., 236, 415; [16] Jess et al., 2010, Solar Phys, 261, 363;
  [17] Watanabe, J-I. et al. 2003, ApJ, 585, L159; [18] Leblanc, F. et
  al. 2008, A&amp;A, 482, 293; [19] Fulle, M. et al. 2013, ApJL, 771, L21

---------------------------------------------------------
Title: Spatially Resolved Spectroscopic Observations of Na and K in
    the Tail of Comet C/2011 L4 (PanSTARRS)
Authors: Cochran, Anita L.; Wooden, D. H.; McKay, A. J.; Cauzzi, G.;
   Reardon, K.; Tozzi, G.
2013DPS....4550205C    Altcode:
  We used the Dunn Solar Telescope (DST) of The National Solar Observatory
  to obtain spectroscopic observations of comet C/2011 L4 (PanSTARRS) on
  13 and 14 March 2013. The DST has the advantage for comet observations
  that one can observe the comet when it is close to the Sun. At the
  time of our observations, comet PanSTARRS was at 0.31 and 0.32 AU
  heliocentric distance. We used the Horizontal Spectrograph to observe
  five different spectral regions of the coma. The resolving power was
  50,000 - 60,000. The slit was 0.3 arcsec wide and 171 arcsec long. At
  the comet's geocentric distance, the slit covered 1.43e5 km. The
  comet was approximately centered on the slit. We observed strong
  emissions from sodium (D1@589.592nm and D2@588.995nm) and potassium
  (D1@770.108nm and D2@671.701nm), along with a weak continuum. Lithium
  was not detected. The sodium was visible on the optocenter and the
  tailward side of the comet and extended to the edge of the slit (i.e. at
  least 70,000km tailward). It shifted redward at larger cometocentric
  distances, attributable to the acceleration of sodium by solar radiation
  pressure. The potassium was much weaker than the sodium and does not
  appear to extend as far from the optocenter. In this paper, we will show
  the distribution of these gases and compare their relative strengths. We
  will discuss the effects of the different photodissociative lifetimes
  of sodium and potassium and how they dictate what we observed.

---------------------------------------------------------
Title: The properties of flare kernels observed by the Dunn Solar
    Telescope
Authors: Fletcher, Lyndsay; Kowalski, A.; Cauzzi, G.; Hawley, S. L.;
   Hudson, H. S.
2013SPD....44...67F    Altcode:
  We report on a campaign at the Dunn Solar Telescope which resulted in
  successful imaging and spectroscopic observations of a C1.1 solar flare
  on 18th August 2011. This flare exhibited ribbons with complicated
  fine structure at the resolution of the DST/IBIS instrument, and a
  number of bright kernels with sizes comparable to the smallest scales
  sampled by IBIS, around 2-4 pixels (0."3-0."6) FWHM. We focus on these
  bright kernels, describing their spatial characteristics in the core
  and wing of H alpha and Ca II 8542, and in the UV and EUV with SDO. We
  also show preliminary broad-band spectroscopy of the kernels which may
  demonstrate the presence of an optical continuum in this small flare.

---------------------------------------------------------
Title: First Results from the EUNIS 2013 Sounding Rocket Campaign
Authors: Daw, Adrian N.; Rabin, D. M.; Brosius, J. W.; Haas, J. P.;
   Plummer, T.; Cauzzi, G.; Reardon, K. P.; Beck, C.
2013SPD....4410501D    Altcode:
  The Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS)
  sounding rocket launched 23 April 2013 at 17:30 UT, as part of a
  campaign including co-ordinated observations with the Dunn Solar
  Telescope/IBIS, Hinode/EIS, SoHO/CDS, RHESSI and SDO. EUNIS obtained
  the highest-resolution observations of the solar spectrum from 52-63 nm
  observed to date, as well as observations with the previously-flown
  waveband from 30-37 nm. The broad spectral coverage of the EUV
  observations includes emission lines of ionization stages from He I to
  Fe XIX, and thus a wide temperature range of 0.025 to 10 MK. Absolute
  radiometric calibration of EUNIS provides underflight calibration of
  CDS, EIS and AIA. Spectra were obtained with a 1.3 s cadence as the
  660-arcsec long slit was rastered across two different regions. The
  observations captured a B-class flare in active region NOAA 11726 as
  well as active regions 11723, 11724, off-limb, quiet sun and a coronal
  hole. We discuss first results from anaysis of this rich and extensive
  data set.

---------------------------------------------------------
Title: Science with Large Solar Telescopes
Authors: Cauzzi, G.; Tritschler, A.; Deng, Y.
2012IAUSS...6E....C    Altcode:
  With several large aperture optical/IR telescopes coming on-line,
  and scheduled for the near future, solar physics is on the verge
  of a quantum leap in observational capabilities. An efficient use
  of such facilities will require new and innovative approaches to
  both observatory operations and data handling. <P />This two-days
  long Special Session will discuss the science expected with large
  solar telescopes, and start addressing the strategies necessary to
  optimize their scientific return. Cutting edge solar science as derived
  from state of the art observations and numerical simulations will be
  presented, and discussions will be held on the role of large facilities
  in satisfying the demanding requirements of spatial and temporal
  resolution, stray-light, and spectro-polarimetric accuracy. Building on
  the experience of recently commissioned telescopes, we will then discuss
  critical issues for the development of future facilities including
  operational issues peculiar to large telecopes, and strategies for
  their best use.

---------------------------------------------------------
Title: The IBIS Mosaic
Authors: Cauzzi, G.; Reardon, K.
2012IAUSS...6E.511C    Altcode:
  Existing and planned instrumentation for large solar telescopes is
  tailored to exploit the high spatial resolution affordable with such
  facilities. However, the typical instrumental tradeoffs restrict the
  field-of-view accessible at once to rather small areas (well below
  100" diameter): this represents a serious impediment for study of
  the active Sun, where large scale magnetic connectivity is of much
  relevance. Mosaicking offers a possibility to obtain high-resolution
  observations over a large FOV, but the technique has been only
  sparsely utilized at ground-based, optical telescopes. In this poster
  we report on an investigation of the feasibility and utility of mosaic
  observations with a state-of-the-art facility, the Interferometric
  BIdimensional Spectrometer instrument (IBIS) installed at the Dunn
  Solar Telescope (NSO). We obtained a 3 x 3 mosaic, covering the full
  AR NOAA 11092 for a total field in excess of 4' x 4', sampling both
  photospheric and chromospheric lines. We report on the methods utilized
  for observation and assembly of the data cubes, and some preliminary
  comparisons with simultaneous observations from other instruments.

---------------------------------------------------------
Title: LEMUR: Large European module for solar Ultraviolet
    Research. European contribution to JAXA's Solar-C mission
Authors: Teriaca, Luca; Andretta, Vincenzo; Auchère, Frédéric;
   Brown, Charles M.; Buchlin, Eric; Cauzzi, Gianna; Culhane, J. Len;
   Curdt, Werner; Davila, Joseph M.; Del Zanna, Giulio; Doschek, George
   A.; Fineschi, Silvano; Fludra, Andrzej; Gallagher, Peter T.; Green,
   Lucie; Harra, Louise K.; Imada, Shinsuke; Innes, Davina; Kliem,
   Bernhard; Korendyke, Clarence; Mariska, John T.; Martínez-Pillet,
   Valentin; Parenti, Susanna; Patsourakos, Spiros; Peter, Hardi; Poletto,
   Luca; Rutten, Robert J.; Schühle, Udo; Siemer, Martin; Shimizu,
   Toshifumi; Socas-Navarro, Hector; Solanki, Sami K.; Spadaro, Daniele;
   Trujillo-Bueno, Javier; Tsuneta, Saku; Dominguez, Santiago Vargas;
   Vial, Jean-Claude; Walsh, Robert; Warren, Harry P.; Wiegelmann,
   Thomas; Winter, Berend; Young, Peter
2012ExA....34..273T    Altcode: 2011ExA...tmp..135T; 2011arXiv1109.4301T
  The solar outer atmosphere is an extremely dynamic environment
  characterized by the continuous interplay between the plasma and the
  magnetic field that generates and permeates it. Such interactions play a
  fundamental role in hugely diverse astrophysical systems, but occur at
  scales that cannot be studied outside the solar system. Understanding
  this complex system requires concerted, simultaneous solar observations
  from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at
  high spatial resolution (between 0.1” and 0.3”), at high temporal
  resolution (on the order of 10 s, i.e., the time scale of chromospheric
  dynamics), with a wide temperature coverage (0.01 MK to 20 MK,
  from the chromosphere to the flaring corona), and the capability of
  measuring magnetic fields through spectropolarimetry at visible and
  near-infrared wavelengths. Simultaneous spectroscopic measurements
  sampling the entire temperature range are particularly important. These
  requirements are fulfilled by the Japanese Solar-C mission (Plan B),
  composed of a spacecraft in a geosynchronous orbit with a payload
  providing a significant improvement of imaging and spectropolarimetric
  capabilities in the UV, visible, and near-infrared with respect to
  what is available today and foreseen in the near future. The Large
  European Module for solar Ultraviolet Research (LEMUR), described
  in this paper, is a large VUV telescope feeding a scientific payload
  of high-resolution imaging spectrographs and cameras. LEMUR consists
  of two major components: a VUV solar telescope with a 30 cm diameter
  mirror and a focal length of 3.6 m, and a focal-plane package composed
  of VUV spectrometers covering six carefully chosen wavelength ranges
  between 170 Å and 1270 Å. The LEMUR slit covers 280” on the Sun with
  0.14” per pixel sampling. In addition, LEMUR is capable of measuring
  mass flows velocities (line shifts) down to 2 km s<SUP> - 1</SUP> or
  better. LEMUR has been proposed to ESA as the European contribution
  to the Solar C mission.

---------------------------------------------------------
Title: Conceptual design of the data handling system for the European
    Solar Telescope
Authors: Ermolli, Ilaria; Cauzzi, Gianna; Collados, Manuel; Paletou,
   Frederic; Reardon, Kevin; Aboudarham, Jean; Cirami, Roberto; Cosentino,
   Rosario; Del Moro, Dario; Di Marcantonio, Paolo; Giorgi, Fabrizio;
   Lafon, Martine; Pietropaolo, Ermanno; Romano, Paolo
2012SPIE.8448E..1SE    Altcode:
  We present an overview of the conceptual design of the data handling
  unit of the ECS, the Control System for the European Solar Telescope
  (EST). We will focus on describing the critical requirements for this
  unit resulting from the overall design of the telescope, together with
  its architecture and the results of the feasibility analysis carried
  out to date.

---------------------------------------------------------
Title: Evidence for Sheet-like Elementary Structures in the Sun's
    Atmosphere?
Authors: Judge, Philip G.; Reardon, Kevin; Cauzzi, Gianna
2012ApJ...755L..11J    Altcode:
  Narrow, thread-like structures in the Sun's chromosphere are currently
  understood to be plasma guided along narrow tubes of magnetic flux. We
  report on 1 s cadence imaging spectroscopic measurements of the Hα
  line with the IBIS Fabry-Pérot instrument at the Dunn Solar Telescope,
  obtained +0.11 nm from line center. Rapid changes grossly exceeding
  the Alfvén speed are commonly seen along the full extent of many
  chromospheric threads. We argue that only an optical superposition
  effect can reasonably explain the data, analogous to striations of
  curtains blowing in the wind. Other explanations appear to require
  significant contrivances to avoid contradicting various aspects of
  the data. We infer that the absorbing plasma exists in two-dimensional
  sheet-like structures within the three-dimensional magnetofluid, related
  perhaps to magnetic tangential discontinuities. This interpretation
  demands a re-evaluation of basic assumptions about low-β solar plasmas,
  as advocated by Parker, with broader implications in astrophysics
  and plasma physics. Diverse, high-cadence observations are needed to
  further define the relationship between magnetic field and thermal
  fine structure.

---------------------------------------------------------
Title: The IBIS Mosaic - A Broad View Of The Solar Atmosphere
Authors: Reardon, Kevin P.; Cauzzi, G.
2012AAS...22020111R    Altcode:
  We present a unique set of observations spanning the photosphere and
  chromosphere with a large field-of-view (4 x 4 arcminutes) ,high-spatial
  resolution (0.1"/pixel), and full spectral profiles (R ∼ 200,000). The
  data were obtained with the IBIS imaging spectrometer at the NSO/Dunn
  Solar Telescope on August 3, 2010 using a mosaic technique to tile an
  active region and surrounding areas. Spectral profiles were obtained
  in the chromospheric Hα, CaII 854.2 nm, and He I D3 lines, as well as
  photospheric FeI 543.4 nm. Combining this dataset with simultaneous
  SDO/AIA and SDO/HMI images and magnetic field measurements allow a
  highly comprehensive view of an entire volume of the solar atmosphere
  from photosphere to corona. The wealth of information is used to
  explore the nature of the chromospheric fibrillar structures and their
  relationship with the overlying corona.

---------------------------------------------------------
Title: Commission 12: Solar Radiation and Structure
Authors: Kosovichev, Alexander; Cauzzi, Gianna; Pillet, Valentin
   Martinez; Asplund, Martin; Brandenburg, Axel; Chou, Dean-Yi;
   Christensen-Dalsgaard, Jorgen; Gan, Weiqun; Kuznetsov, Vladimir D.;
   Rovira, Marta G.; Shchukina, Nataliya; Venkatakrishnan, P.
2012IAUTA..28...81K    Altcode: 2012IAUTB..28...81K
  Commission 12 of the International Astronomical Union encompasses
  investigations of the internal structure and dynamics of the Sun, mostly
  accessible through the techniques of local and global helioseismology,
  the quiet solar atmosphere, solar radiation and its variability, and
  the nature of relatively stable magnetic structures like sunspots,
  faculae and the magnetic network. The Commission sees participation
  of over 350 scientists worldwide.

---------------------------------------------------------
Title: Division II: Sun and Heliosphere
Authors: Martínez Pillet, Valentín; Klimchuk, James A.; Melrose,
   Donald B.; Cauzzi, Gianna; van Driel-Gesztelyi, Lidia; Gopalswamy,
   Natchimuthuk; Kosovichev, Alexander; Mann, Ingrid; Schrijver,
   Carolus J.
2012IAUTA..28...61M    Altcode: 2012IAUTA..28...61P
  The solar activity cycle entered a prolonged quiet phase that started
  in 2008 and ended in 2010. This minimum lasted for a year longer
  than expected and all activity proxies, as measured from Earth and
  from Space, reached minimum values never observed before (de Toma,
  2012). The number of spotless days from 2006 to 2009 totals 800, the
  largest ever recorded in modern times. Solar irradiance was at historic
  minimums. The interplanetary magnetic field was measured at values as
  low as 2.9 nT and the cosmic rays were observed at records-high. While
  rumors spread that the Sun could be entering a grand minimum quiet
  phase (such as the Maunder minimum of the XVII century), activity
  took over in 2010 and we are now well into Solar Cycle 24 (albeit,
  probably, a low intensity cycle), approaching towards a maximum due
  by mid 2013. In addition to bringing us the possibility to observe
  a quiet state of the Sun and of the Heliosphere that was previously
  not recorded with modern instruments, the Sun has also shown us how
  little we know about the dynamo mechanism that drives its activity as
  all solar cycle predictions failed to see this extended minimum coming.

---------------------------------------------------------
Title: New insight on the coupling of the solar atmosphere from
    imaging spectroscopy
Authors: Reardon, K.; Cauzzi, G.
2012decs.confE..20R    Altcode:
  We present spectrally resolved, high-resolution observations of
  chromospheric diagnostics obtained with IBIS covering a full active
  region. In particular, the data includes the first high-resolution
  observations of the He I D3 line (587.6 nm), a subordinate of the more
  famous HeI 1083.0 nm line, showing loops and other structures on the
  solar disk at the 150 km diffraction limit. The large FOV of our data
  allows a meaningfully comparison with the SDO full disk observations
  to investigate the coupling between different portions of the solar
  atmosphere and the topology of the chromospheric magnetic field. The
  relationship between the chromospheric signatures and the SDO 304 Å and
  171 Å emission provides intriguing hints to the existence of low-lying
  loops at TR temperatures effectively disconnected from the corona.

---------------------------------------------------------
Title: Data handling and control  of the European Solar Telescope
Authors: Ermolli, I.; Bettonvil, F.; Cauzzi, G.; Cavaller, L.;
   Collados, M.; Di Marcantonio, P.; Grivel, C.; Paletou, F.; Romano,
   P.; Aboudarham, J.; Cirami, R.; Cosentino, R.; Giorgi, F.; Lafon,
   M.; Laforgue, D.; Reardon, K.; Sliepen, G.
2012MSAIS..19..380E    Altcode:
  We describe some aspects of the facility operation that have been
  considered for the design of the data handling and control of the
  European Solar Telescope. The main sub-systems of the EST relevant for
  the control are summarized, together with some information on current
  solar data models.

---------------------------------------------------------
Title: Splinter Session "Solar and Stellar Flares"
Authors: Fletcher, L.; Hudson, H.; Cauzzi, G.; Getman, K. V.; Giampapa,
   M.; Hawley, S. L.; Heinzel, P.; Johnstone, C.; Kowalski, A. F.; Osten,
   R. A.; Pye, J.
2011ASPC..448..441F    Altcode: 2011csss...16..441F; 2012arXiv1206.3997F
  This summary reports on papers presented at the Cool Stars-16 meeting in
  the splinter session "Solar and Stellar flares." Although many topics
  were discussed, the main themes were the commonality of interests,
  and of physics, between the solar and stellar flare communities,
  and the opportunities for important new observations in the near future.

---------------------------------------------------------
Title: Data handling and control for the European Solar Telescope
Authors: Ermolli, Ilaria; Bettonvil, Felix; Cauzzi, Gianna; Cavaller,
   Lluis; Collados, Manuel; Di Marcantonio, Paolo; Paletou, Frederic;
   Romano, Paolo; Aboudarham, Jean; Cirami, Roberto; Cosentino, Rosario;
   Giorgi, Fabrizio; Lafon, Martine; Laforgue, Didier; Reardon, Kevin;
   Sliepen, Guus
2010SPIE.7740E..0GE    Altcode: 2010SPIE.7740E..13E
  We introduce the concepts for the control and data handling systems of
  the European Solar Telescope (EST), the main functional and technical
  requirements for the definition of these systems, and the outcomes
  from the trade-off analysis to date. Concerning the telescope control,
  EST will have performance requirements similar to those of current
  medium-sized night-time telescopes. On the other hand, the science
  goals of EST require the simultaneous operation of three instruments
  and of a large number of detectors. This leads to a projected data
  flux that will be technologically challenging and exceeds that of
  most other astronomical projects. We give an overview of the reference
  design of the control and data handling systems for the EST to date,
  focusing on the more critical and innovative aspects resulting from
  the overall design of the telescope.

---------------------------------------------------------
Title: The ADAHELI solar mission: Investigating the structure of
    Sun's lower atmosphere
Authors: Berrilli, F.; Bigazzi, A.; Roselli, L.; Sabatini, P.; Velli,
   M.; Alimenti, F.; Cavallini, F.; Greco, V.; Moretti, P. F.; Orsini,
   S.; Romoli, M.; White, S. M.; ADAHELI Team; Ascani, L.; Carbone, V.;
   Curti, F.; Consolini, G.; Di Mauro, M. P.; Del Moro, D.; Egidi, A.;
   Ermolli, I.; Giordano, S.; Pastena, M.; Pulcino, V.; Pietropaolo, E.;
   Romano, P.; Ventura, P.; Cauzzi, G.; Valdettaro, L.; Zuccarello, F.;
   ADAHELI Team
2010AdSpR..45.1191B    Altcode: 2010AdSpR..45.1191A
  ADAHELI (ADvanced Astronomy for HELIophysics) is a small-class
  (500 kg) low-budget (50 MEuro) satellite mission for the study of
  the solar photosphere and the chromosphere and for monitoring solar
  flare emission. ADAHELI's design has completed its Phase-A feasibility
  study in December 2008, in the framework of ASI's (Agenzia Spaziale
  Italiana) 2007 "Small Missions" Program (calling for two missions at
  50 MEeuros each, plus the launch budget). ADAHELI's main purpose is
  to explore Sun's lower atmosphere in the near-infrared, a region so
  far unexplored by solar observations from space. ADAHELI will carry
  out observations of the solar photosphere and of the chromosphere at
  high-temporal rate and high spatial and spectral resolutions. ADAHELI
  will contribute to the understanding of Space Weather through the
  study of particle acceleration during flares. A radiometer operating
  in the millimeter radio band will continuously monitor the solar disk,
  throughout the spacecraft's life time. ADAHELI's baseline instruments
  are a 50-cm high-resolution telescope operating in the visible and
  the near-infrared, and a lightweight full-disk radiometer operating at
  millimeter wavelengths (90 GHz). The core of the telescope's focal plane
  suite is the spectral imager based on two Fabry-Perot interferometers,
  flying for the first time on a solar mission. The instrument
  will return fast-cadence, full bi-dimensional spectral images at
  high-resolution, thus improving on current slit-scan, mono-dimensional
  architectures. Moreover, the possibility of working in polarized light
  will enable full 3D magnetic field reconstruction on the photosphere
  and the chromosphere. An optional instrumental package is also being
  proposed to further extend ADAHELI's scope: a full-disk telescope for
  helioseismology based on a double Magneto-Optical Filter, a Neutral
  Particle Analyzer for magnetospheric research, an Extreme Ultraviolet
  imaging and spectro-radiometry instrument. These options fall outside
  the prescribed budget. ADAHELI, flying a Sun-Synchronous orbit at 800
  km, will perform continuous, long-duration (4-h), daily acquisitions,
  with the possibility of extending them up to 24 h. ADAHELI's operating
  life is two years, plus one extension year. Launch would be nominally
  planned for 2014.

---------------------------------------------------------
Title: Delving into the Chromosphere: New Observational Tools
Authors: Reardon, Kevin P.; Cauzzi, G.; Tritschler, A.; Uitenbroek, H.
2010AAS...21630503R    Altcode:
  The chromosphere lies at the boundary between the near-equilibrium
  photosphere and the hot, expanding corona. This region combines both
  large interconnecting magnetic structures, and fine-scaled dynamics into
  an intriguingly complex whole. Studying this behavior is a significant
  observational challenge, requiring sizable fields of view (60-90")
  sampled at high spatial (&lt; 0.3") and temporal resolution (&lt; 30
  seconds), with full spectral information in multiple lines. We will
  describe how instruments based on Fabry-Perot interferometers have
  recently begun to routinely deliver such observations. We will review
  some of the most exciting results obtained and the deeper insights
  they have provided into the characteristics of the solar chromosphere.

---------------------------------------------------------
Title: Fabry-Pérot Versus Slit Spectropolarimetry of Pores and
Active Network: Analysis of IBIS and Hinode Data
Authors: Judge, Philip G.; Tritschler, Alexandra; Uitenbroek, Han;
   Reardon, Kevin; Cauzzi, Gianna; de Wijn, Alfred
2010ApJ...710.1486J    Altcode: 2010arXiv1001.0561J
  We discuss spectropolarimetric measurements of photospheric (Fe I
  630.25 nm) and chromospheric (Ca II 854.21 nm) spectral lines in and
  around small magnetic flux concentrations, including a pore. Our
  long-term goal is to diagnose properties of the magnetic field
  near the base of the corona. We compare ground-based two-dimensional
  spectropolarimetric measurements with (almost) simultaneous space-based
  slit spectropolarimetry. We address the question of noise and crosstalk
  in the measurements and attempt to determine the suitability of Ca II
  measurements with imaging spectropolarimeters for the determination
  of chromospheric magnetic fields. The ground-based observations
  were obtained 2008 May 20, with the Interferometric Bidimensional
  Spectrometer (IBIS) in spectropolarimetric mode operated at the Dunn
  Solar Telescope at Sunspot, NM. The space observations were obtained
  with the Spectro-Polarimeter of the Solar Optical Telescope aboard the
  Japanese Hinode satellite. The agreement between the near-simultaneous
  co-spatial IBIS and Hinode Stokes-V profiles at 630.25 nm is
  excellent, with V/I amplitudes compatible to within 1%. The IBIS QU
  measurements are affected by residual crosstalk from V, arising from
  calibration inaccuracies, not from any inherent limitation of imaging
  spectroscopy. We use a Principal Component Analysis to quantify the
  detected crosstalk. QU profiles with V crosstalk subtracted are in
  good agreement with the Hinode measurements, but are noisier owing to
  fewer collected photons. Chromospheric magnetic fields are notoriously
  difficult to constrain by polarization of Ca II lines alone. However,
  we demonstrate that high cadence, high angular resolution monochromatic
  images of fibrils in Ca II and Hα, seen clearly in IBIS observations,
  can be used to improve the magnetic field constraints, under conditions
  of high electrical conductivity. Such work is possible only with time
  series data sets from two-dimensional spectroscopic instruments such
  as IBIS, under conditions of good seeing.

---------------------------------------------------------
Title: Dual-Line Spectral Imaging of the Chromosphere
Authors: Cauzzi, G.; Reardon, K.; Rutten, R. J.; Tritschler, A.;
   Uitenbroek, H.
2010ASSP...19..513C    Altcode: 2010mcia.conf..513C
  Hα filtergrams are notoriously difficult to interpret, "beautiful
  to view but not fit for analysis." We try to remedy this by using
  the IBIS bi-dimensional spectrometer at the Dunn Solar Telescope at
  NSO/Sacramento Peak to compare the quiet-sun chromosphere observed in
  Hα to what is observed simultaneously in Ca II 854.2 nm, sampling both
  lines with high angular and spectral resolution and extended coverage
  of space, time, and wavelength. Per (x, y, t) pixel we measured the
  intensity and Dopplershift of the minimum of each line's profile at
  that pixel, as well as the width of their inner chromospheric cores. A
  paper submitted to A&amp;A (December 2008) compares these measurements
  in detail.

---------------------------------------------------------
Title: Service-Mode Observations for Ground-Based Solar Physics
Authors: Reardon, K. P.; Rimmele, T.; Tritschler, A.; Cauzzi, G.;
   Wöger, F.; Uitenbroek, H.; Tsuneta, S.; Berger, T.
2009ASPC..415..332R    Altcode: 2009arXiv0909.1522R
  There are significant advantages in combining Hinode observations
  with ground-based instruments that can observe additional spectral
  diagnostics at higher data rates and with greater flexibility. However,
  ground-based observations, because of the random effects of weather
  and seeing as well as the complexities data analysis due to changing
  instrumental configurations, have traditionally been less efficient
  than satellite observations in producing useful datasets. Future large
  ground-based telescopes will need to find new ways to optimize both
  their operational efficiency and scientific output. <P />We have begun
  experimenting with service-mode or queue-mode observations at the Dunn
  Solar Telescope using the Interferometric Bidimensional Spectrometer
  (IBIS) as part of joint Hinode campaigns. We describe our experiences
  and the advantag es of such an observing mode for solar physics.

---------------------------------------------------------
Title: The solar chromosphere at high resolution with
    IBIS. IV. Dual-line evidence of heating in chromospheric network
Authors: Cauzzi, G.; Reardon, K.; Rutten, R. J.; Tritschler, A.;
   Uitenbroek, H.
2009A&A...503..577C    Altcode: 2009arXiv0906.2083C
  The structure and energy balance of the solar chromosphere remain
  poorly known. We used the imaging spectrometer IBIS at the Dunn Solar
  Telescope to obtain fast-cadence, multi-wavelength profile sampling
  of Hα and Ca ii 854.2 nm over a sizable two-dimensional field of view
  encompassing quiet-Sun network. We provide a first inventory of how the
  quiet chromosphere appears in these two lines by comparing basic profile
  measurements in the form of image displays, temporal-average displays,
  time slices, and pixel-by-pixel correlations. We find that the two lines
  can be markedly dissimilar in their rendering of the chromosphere,
  but that, nevertheless, both show evidence of chromospheric heating,
  particularly in and around network: Hα in its core width and Ca ii
  854.2 nm in its brightness. We discuss venues for improved modeling.

---------------------------------------------------------
Title: The solar chromosphere at high resolution with
    IBIS. III. Comparison of Ca II K and Ca II 854.2 nm imaging
Authors: Reardon, K. P.; Uitenbroek, H.; Cauzzi, G.
2009A&A...500.1239R    Altcode: 2008arXiv0810.5260R
  Aims: Filtergrams obtained in Ca II H, Ca II K, and Hα are often
  employed as diagnostics of the solar chromosphere. The vastly disparate
  appearance between the typical filtergrams in these different lines
  calls into question the nature of what is actually being observed. We
  investigate the lack of obvious structures of magnetic origin such as
  fibrils and mottles in on-disk Ca II H and K images. <BR />Methods: We
  directly compare a temporal sequence of classical Ca II K filtergrams
  with a co-spatial and co-temporal sequence of spectrally resolved
  Ca II 854.2 images obtained with the Interferometric Bidimensional
  Spectrometer (IBIS), considering the effect of both the spectral and
  spatial smearing. We analyze the temporal behavior of the two series
  by means of Fourier analysis. <BR />Results: The lack of fine magnetic
  structuring in Ca II K filtergrams, even with the narrowest available
  filters, is due to observational effects, primarily contributions from
  the bright, photospheric wings of the line that swamp the small and
  dark chromospheric structures. Signatures of fibrils remain, however,
  in the temporal evolution of the filtergrams, in particular with
  the evidence of magnetic shadows around the network elements. The
  Ca II K filtergrams do not appear, however, to properly reflect the
  high-frequency behavior of the chromosphere. Using the same analysis,
  we find no significant chromospheric signature in the Hinode/SOT Ca II
  H quiet-Sun filtergrams. <BR />Conclusions: The picture provided by Hα
  and Ca II 854.2, which show significant portions of the chromosphere
  dominated by magnetic structuring, appears to reflect the true and
  essential nature of the solar chromosphere. Data that do not resolve
  this aspect, whether spatially or spectrally, may misrepresent the
  behavior the chromosphere.

---------------------------------------------------------
Title: The solar chromosphere at high resolution with
    IBIS. II. Acoustic shocks in the quiet internetwork and the role of
    magnetic fields
Authors: Vecchio, A.; Cauzzi, G.; Reardon, K. P.
2009A&A...494..269V    Altcode: 2008arXiv0807.4966V
  Context: The exact nature of the quiet solar chromosphere and
  especially its temporal variation, are still subjects of intense
  debate. One of the contentious issues is the possible role of the
  magnetic field in structuring the quieter solar regions. <BR />Aims:
  We characterize the dynamics of the quiet inter-network chromosphere
  by studying the occurrence of acoustic shocks and their relation with
  the concomitant photospheric structure and dynamics, including small
  scale magnetic structures. <BR />Methods: We analyze a comprehensive
  data set that includes high-resolution chromospheric (Ca ii 854.2
  nm) and photospheric (Fe i 709.0 nm) spectra obtained with the IBIS
  imaging spectrometer in two quiet-Sun regions. This is complemented by
  high-resolution sequences of MDI magnetograms of the same targets. From
  the chromospheric spectra we identify the spatio-temporal occurrence of
  the acoustic shocks. We compare it with the photospheric dynamics by
  means of both Fourier and wavelet analysis and study the influence of
  magnetic structures on the phenomenon. <BR />Results: Mid-chromospheric
  shocks occur within the general chromospheric dynamics pattern of
  acoustic waves propagating from the photosphere. In particular, they
  appear as a response to underlying powerful photospheric motions
  at periodicities nearing the acoustic cut-off, consistent with 1-D
  hydrodynamical modeling. However, their spatial distribution within
  the supergranular cells is highly dependent on the local magnetic
  topology, both at the network and internetwork scale. We find that
  large portions of the internetwork regions undergo very few shocks,
  since they are “shadowed” by the horizontal component of the
  magnetic field. The latter is betrayed by the presence of chromospheric
  fibrils, observed in the core of the Ca ii line as slanted structures
  with distinct dynamical properties. The shadow mechanism also appears
  to operate on the very small scales of inter-network magnetic elements,
  and provides for a very pervasive influence of the magnetic field even
  in the quietest region analyzed. <BR />Conclusions: The magnetic field
  might play a larger role in structuring the quiet solar chromosphere
  than normally assumed. The presence of fibrils highlights a clear
  disconnection between the photospheric dynamics and the response of
  the geometrically overlaying chromosphere. As these results hold for
  a mid-chromospheric indicator such as the Ca ii 854.2 line, it is
  expected that diagnostics formed in higher layers, such as UV lines
  and continua, will be affected to a greater extent by the presence
  of magnetic fields, even in quiet regions. This is relevant for the
  chromospheric models that make use of such diagnostics.

---------------------------------------------------------
Title: The Solar Chromosphere: Old Challenges, New Frontiers
Authors: Ayres, T.; Uitenbroek, H.; Cauzzi, G.; Reardon, K.; Berger,
   T.; Schrijver, C.; de Pontieu, B.; Judge, P.; McIntosh, S.; White,
   S.; Solanki, S.
2009astro2010S...9A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Commission 12: Solar Radiation and Structure
Authors: Martínez Pillet, Valentin; Kosovichev, Alexander;
   Mariska, John T.; Bogdan, Thomas J.; Asplund, Martin; Cauzzi, Gianna;
   Christensen-Dalsgaard, Jørgen; Cram, Lawrence E.; Gan, Weiqun; Gizon,
   Laurent; Heinzl, Petr; Rovira, Marta G.; Venkatakrishnan, P.
2009IAUTA..27..104M    Altcode:
  Commission 12 encompasses investigations on the internal structure
  and dynamics of the Sun, mostly accessible through the techniques of
  local and global helioseismology, the quiet solar atmosphere, solar
  radiation and its variability, and the nature of relatively stable
  magnetic structures like sunspots, faculae and the magnetic network. A
  revision of the progress made in these fields is presented. For some
  specific topics, the review has counted with the help of experts
  outside the Commission Organizing Committee that are leading and/or
  have recently presented relevant works in the respective fields. In
  this cases the contributor's name is given in parenthesis.

---------------------------------------------------------
Title: The ADAHELI Solar Mission
Authors: Berrilli, F.; Velli, M.; Roselli, L.; Bigazzi, A.; Moretti,
   P. F.; Romoli, M.; Orsini, S.; Cavallini, F.; Greco, V.; Carbone,
   V.; Consolini, G.; Di Mauro, M. P.; Ermolli, I.; Pietropaolo, E.;
   Romano, P.; Ventura, P.; White, S. M.; Zuccarello, F.; Cauzzi, G.;
   Valdettaro, L.
2008ESPM...12..6.6B    Altcode:
  ADAHELI (Advanced Astronomy for HELIOphysics) is an Italian Space
  project for the investigation of solar photospheric and chromospheric
  dynamics, via high-resolution spectro-polarimetric observations in the
  near-infrared spectral range. The mission has been financed for phase
  A study in the framework of ASI Italian Space Agency Small Missions
  Program call of September 2007. <P />Four fields have been selected
  to highlight the specific benefits of ADAHELI scientific payload: 1)
  Photospheric and chromospheric dynamics and structure, 2) Emergence and
  evolution of solar active regions and solar irradiance, 3) Chromospheric
  and corona heating and turbulence, 4) Solar flares in the millimeter
  wavelength region. <P />The principal science instrument, ISODY, is
  a 50 cm solar telescope equipped with an innovative Focal Plane Suite
  composed of a spectro-polarimetric imager, based upon two Fabry-Perot
  interferometers operating in the NIR regions around 845nm and 1083nm, a
  broad band imager, and a correlation tracker used as image stabilization
  system. <P />Designed Mission Profiles for ADAHELI intend to achieve
  continuous high-spectral and spatial resolution observations of the
  Sun for a routine duration of 4 hours with a goal to be extended to
  24 hours. <P />ADAHELI also carries MIOS, a millimeter wavelengths
  radiometer operating at around 90 GHz for flare detection. <P />The
  ADAHELI payload's instrument suite integrates and complements, without
  overlap, the present major objectives of ESA, NASA and the International
  Living with a Star program, in particular Solar Dynamics Observatory,
  PICARD, Solar Orbiter, and the Solar Probe missions. <P />Proposals
  for optional instruments are also under evaluation: DIMMI-2h, a
  double channel MOF based full disk imager operating at 589nm and
  770nm, allowing high temporal resolution velocity and magnetic field
  measurements; EISR a two channel spectrometer operating in the 50-130
  nm wavelength range, and NPA, an in-situ Neutral Particle Analyzer
  to detect Energetic Neutral Atoms (ENA). Science objectives related
  to optional instruments include: solar high and low-degree p modes
  oscillations, EUV solar structures and variability, solar gravitational
  red-shift measurement, detection of ENA originating from the plasma
  region in the Earth's magnetosphere and undergoing reflection from
  the Earth's atmosphere.

---------------------------------------------------------
Title: Acoustic Shocks in the Quiet Internetwork and the Role of
    Magnetic Fields
Authors: Cauzzi, G.; Vecchio, A.; Reardon, K.
2008ESPM...12.2.37C    Altcode:
  By using imaging spectroscopy in the CaII 854.2 nm line obtained with
  IBIS over several quiet Sun regions, we present compelling evidence of
  acoustic shocks occurring in the quiet chromosphere at the dominant
  3-minute periodicity. The shocks present many of the characteristics
  prescribed in 1-D hydrodynamics models, including a mostly vertical
  propagation of the disturbance from regions of enhanced photospheric
  velocity at periodicities close to the acoustic cut-off. <P />Our most
  interesting result, however, is the large influence that magnetic
  structures exert on the development of chromospheric shocks. In
  particular, shocks are essentially absent from extended regions
  around magnetic network elements, creating the so-called "magnetic
  shadows". These areas coincide with the presence of chromospheric
  fibrils rooted in the network itself, that apparently absorb or
  otherwise modify the upward propagating acoustic waves, inhibiting
  the formation of shocks. <P />Intriguingly, we also find a clear
  reduction in the number of shocks observed in quiet internetwork areas
  whenever small magnetic structures are seen in MDI HR maps. This is
  true even when strong photospheric motions at the relevant periods
  are present. This might imply the need to reevaluate the acoustic
  contribution to the observed chromospheric "basal" flux.

---------------------------------------------------------
Title: Chromospheric Counterparts of UV Explosive Events
Authors: Reardon, K.; Cauzzi, G.; Teriaca, L.; Pitterle, M.; Curdt, W.
2008ESPM...12.2.17R    Altcode:
  We present a study of a unique, multi-wavelength dataset of a quiet
  sun region with the primary goal of studying explosive events at
  chromospheric and transition region heights. Several hypotheses
  have been made about the nature of the explosive events, however the
  underlying mechanisms remain elusive due to their small spatial and
  temporal scales. Several theoretical models predict an important
  role for the chromosphere in the triggering of these events. <P
  />To shed light on this issue, we have obtained a comprehensive
  set of simultaneous high spatial, spectral, and temporal resolution
  observations on April 18, 2007, combining both ground- and space-based
  observatories. Most importantly, we carried out coordinated observations
  with SUMER in the transition region Si IV 140.2 nm line together
  with high-cadence IBIS imaging spectroscopy of the chromospheric CaII
  854.2 nm line. This allows us to examine the chromospheric dynamics
  and acoustic shocks that underlie the transition region events. We
  also use SOT/NFI magnetograms to examine the relation of the explosive
  events to the changes in the magnetic topology. The combined dataset
  also includes Hinode/EIS rasters and Hinode/XRT images that provide
  information on the higher-temperature coronal response.

---------------------------------------------------------
Title: On the Role of Acoustic-gravity Waves in the Energetics of
    the Solar Atmosphere
Authors: Straus, T.; Fleck, B.; Jefferies, S. M.; Cauzzi, G.; McIntosh,
   S. W.; Reardon, K.; Severino, G.; Steffen, M.; Suter, M.; Tarbell,
   T. D.
2008ESPM...12.2.11S    Altcode:
  We revisit the dynamics and energetics of the solar atmosphere, using a
  combination of high-quality observations and 3D numerical simulations
  of the overshoot region of compressible convection into the stable
  photosphere. We discuss the contribution of acoustic-gravity waves
  to the energy balance of the photosphere and low chromosphere. We
  demonstrate the presence of propagating internal gravity waves at
  low frequencies (&lt; 5mHz). Surprisingly, these waves are found
  to be the dominant phenomenon in the quiet middle/upper photosphere
  and to transport a significant amount of mechanical energy into the
  atmosphere outweighing the contribution of high-frequency (&gt; 5mHz)
  acoustic waves by more than an order of magnitude. We compare the
  properties of high-frequency waves in the simulations with results
  of recent high cadence, high resolution Doppler velocity measurements
  obtained with SOT/SP and SOT/NFI on Hinode. Our results seem to be in
  conflict with the simple picture of upward propagating sound waves. We
  discuss the implications of our findings on the energy flux estimate
  at high-frequencies.

---------------------------------------------------------
Title: Physical Properties of Chromospheric Structures in H-alpha
    and and CaII 854.2 nm
Authors: Bostanci, Z. F.; Rutten, R., R. Jtenbroek, H.; Reardon, K.;
   Cauzzi, G.
2008ESPM...12.2.45B    Altcode:
  Comprehensive studies of chromospheric structures are the key to
  understanding their dynamics in different solar regimes and their
  contribution in heating of the solar atmosphere. High spatial and
  spectral resolution observations of a quiet chromospheric region
  were obtained with the Interferometric BIdimensional Spectrometer
  (IBIS) installed at the Dunn Solar Telescope (DST) of the National
  Solar Observatory (NSO) on Sacramento Peak, USA. Chromospheric fibrils
  that were observed simultaneously in the Balmer H? and CaII 854.2 nm
  line are analysed using the cloud model technique to derive numerical
  values for the standard cloud model parameters; optical thickness,
  source function, Dopplerwidth and Dopplershift for the two lines,
  enabling detailed comparison between these.

---------------------------------------------------------
Title: The Energy Flux of Internal Gravity Waves in the Lower Solar
    Atmosphere
Authors: Straus, Thomas; Fleck, Bernhard; Jefferies, Stuart M.;
   Cauzzi, Gianna; McIntosh, Scott W.; Reardon, Kevin; Severino, Giuseppe;
   Steffen, Matthias
2008ApJ...681L.125S    Altcode:
  Stably stratified fluids, such as stellar and planetary atmospheres,
  can support and propagate gravity waves. On Earth these waves,
  which can transport energy and momentum over large distances and can
  trigger convection, contribute to the formation of our weather and
  global climate. Gravity waves also play a pivotal role in planetary
  sciences and modern stellar physics. They have also been proposed
  as an agent for the heating of stellar atmospheres and coronae, the
  exact mechanism behind which is one of the outstanding puzzles in solar
  and stellar physics. Using a combination of high-quality observations
  and 3D numerical simulations we have the first unambiguous detection
  of propagating gravity waves in the Sun's (and hence a stellar)
  atmosphere. Moreover, we are able to determine the height dependence of
  their energy flux and find that at the base of the Sun's chromosphere it
  is around 5 kW m<SUP>-2</SUP>. This amount of energy is comparable to
  the radiative losses of the entire chromosphere and points to internal
  gravity waves as a key mediator of energy into the solar atmosphere.

---------------------------------------------------------
Title: Search for High Velocities in the Disk Counterpart of Type
    II Spicules
Authors: Langangen, Ø.; De Pontieu, B.; Carlsson, M.; Hansteen,
   V. H.; Cauzzi, G.; Reardon, K.
2008ApJ...679L.167L    Altcode: 2008arXiv0804.3256L
  Recently, De Pontieu and coworkers discovered a class of spicules
  that evolve more rapidly than previously known spicules, with rapid
  apparent motions of 50-150 km s<SUP>-1</SUP>, thickness of a few 100
  km, and lifetimes of order 10-60 s. These so-called type II spicules
  have been difficult to study because of limited spatiotemporal and
  thermal resolution. Here we use the IBIS instrument to search for the
  high velocities in the disk counterpart of type II spicules. We have
  detected rapidly evolving events, with lifetimes that are less than a
  minute and often equal to the cadence of the instrument (19 s). These
  events are characterized by a Doppler shift that only appears in the
  blue wing of the Ca II IR line. Furthermore, the spatial extent,
  lifetime, and location near network all suggest a link to type II
  spicules. However, the magnitude of the measured Doppler velocity is
  significantly lower than the apparent motions seen at the limb. We
  use Monte Carlo simulations to show that this discrepancy can be
  explained by a forward model in which the visibility on the disk of
  the high-velocity flows in these events is limited by a combination
  of line-of-sight projection and reduced opacity in upward propelled
  plasma, especially in reconnection driven jets that are powered by a
  roughly constant energy supply.

---------------------------------------------------------
Title: Solar Chromospheric Dynamics: Onwards and Upwards
Authors: Cauzzi, G.; Reardon, K.; Rimmele, T.; Rutten, R.; Tritschler,
   A.; Uitenbroek, H.; Woeger, F.
2008AGUSMSP41B..03C    Altcode:
  We present a study of chromospheric dynamics and its relation with the
  driving photospheric magneto-convection in a variety of solar targets,
  from quiet Sun to more active regions. To this end high resolution
  observations were obtained in CaII 854.2 nm, Hα, and photospheric
  FeI lines with the Interferometric BIdimensional Spectrometer (IBIS)
  installed at the Dunn Solar Telescope of the NSO. The availability of
  full spectroscopic information on extended fields of view allows us
  to derive a comprehensive view of the intrinsically 3-D chromospheric
  scene. A coherent picture is emerging that involves the propagation
  and dissipation of photospheric acoustic waves into the chromospheric
  layers, but selected and guided by the local and highly variable
  magnetic topology. In particular, ubiquitous fibrilar structures,
  apparently originating from even the smallest magnetic elements,
  appear an integral part of the dynamic chromosphere.

---------------------------------------------------------
Title: WHI Targeted Campaigns on Coronal Holes and Quiet Sun: High
    Resolution Observations of the Lower Atmosphere With IBIS
Authors: Cauzzi, G.; Reardon, K. P.; Rimmele, T.; Tritschler, A.;
   Uitebroek, H.; Woeger, F.; Deforest, C.; McIntosh, S.
2008AGUSMSH51A..02C    Altcode:
  The Interferometric BIdimensional Spectrometer (IBIS) is a dual
  Fabry-Perot instrument installed at the Dunn Solar Telescope that allows
  two-dimensional spectroscopic observations in a variety of spectral
  lines. The IBIS/DST will participate in the WHI targeted campaigns
  on coronal holes (April 3-9) and quiet Sun dynamics (April 10-16)
  performing simultaneous high-resolution observations of the dynamics of
  the photosphere and chromosphere in the coordinated targets. The aim is
  to obtain insights on the role of the lower atmosphere's dynamics and
  energetics into the structuring of the coronal plasma and, possibly,
  into the origin of the solar wind. In this paper we will present the
  observations obtained as well as first results, and attempt to relate
  them with recent work performed on quiet Sun chromospheric dynamics.

---------------------------------------------------------
Title: The solar chromosphere at high resolution with IBIS. I. New
    insights from the Ca II 854.2 nm line
Authors: Cauzzi, G.; Reardon, K. P.; Uitenbroek, H.; Cavallini, F.;
   Falchi, A.; Falciani, R.; Janssen, K.; Rimmele, T.; Vecchio, A.;
   Wöger, F.
2008A&A...480..515C    Altcode: 2007arXiv0709.2417C
  Context: The chromosphere remains a poorly understood part of the solar
  atmosphere, as current modeling and observing capabilities are still
  ill-suited to investigating its fully 3-dimensional nature in depth. In
  particular, chromospheric observations that can preserve high spatial
  and temporal resolution while providing spectral information over
  extended fields of view are still very scarce. <BR />Aims: In this
  paper, we seek to establish the suitability of imaging spectroscopy
  performed in the Ca II 854.2 nm line as a means of investigating
  the solar chromosphere at high resolution. <BR />Methods: We utilize
  monochromatic images obtained with the Interferometric BIdimensional
  Spectrometer (IBIS) at multiple wavelengths within the Ca II 854.2 nm
  line and over several quiet areas. We analyze both the morphological
  properties derived from narrow-band monochromatic images and the
  average spectral properties of distinct solar features such as network
  points, internetwork areas, and fibrils. <BR />Results: The spectral
  properties derived over quiet-Sun targets are in full agreement with
  earlier results obtained with fixed-slit spectrographic observations,
  highlighting the reliability of the spectral information obtained
  with IBIS. Furthermore, the very narrowband IBIS imaging reveals very
  clearly the dual nature of the Ca II 854.2 nm line. Its outer wings
  gradually sample the solar photosphere, while the core is a purely
  chromospheric indicator. The latter displays a wealth of fine structures
  including bright points akin to the Ca II H{2V} and K{2V} grains, and
  as fibrils originating from even the smallest magnetic elements. The
  fibrils occupy a large fraction of the observed field of view, even
  in the quiet regions, and clearly outline atmospheric volumes with
  different dynamical properties, strongly dependent on the local magnetic
  topology. This highlights how 1D models stratified along the vertical
  direction can provide only a very limited representation of the actual
  chromospheric physics. <BR />Conclusions: Imaging spectroscopy in the
  Ca II 854.2 nm line currently represents one of the best observational
  tools for investigating the highly structured and highly dynamical
  chromospheric environment. A high-performance instrument such as IBIS
  is crucial in achieving the necessary spectral purity and stability,
  spatial resolution, and temporal cadence. <P />Two movies are only
  available in electronic form at http://www.aanda.org

---------------------------------------------------------
Title: Comparison of spatially and spectrally resolved solar data
    with numerical simulations
Authors: Cauzzi, G.; Asensio Ramos, A.; Reardon, K. P.; Janssen, K.
2007IAUS..239..138C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Reversed granulation in mid-photosphere of the Sun
Authors: Janssen, Katja; Cauzzi, Gianna
2007IAUS..239..163J    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Acoustic Shocks in the Quiet Solar Chromosphere
Authors: Cauzzi, G.; Reardon, K. P.; Vecchio, A.; Janssen, K.;
   Rimmele, T.
2007ASPC..368..127C    Altcode:
  We exploit the two-dimensional spectroscopic capabilities of the
  Interferometric BIdimensional Spectrometer (IBIS) to study the
  chromospheric Ca II 854.2 nm line and its temporal evolution in a quiet
  region at the center of the solar disk. The Ca II 854.2 profiles in the
  internetwork portion of the field of view clearly indicate the presence
  of hydrodynamic shocks, occurring at frequencies above the acoustic
  cut-off. <P />The location and strength of such shocks perfectly map
  the areas where large velocity power is found at frequencies of 5.5-8
  mHz in a standard Fourier analysis. The shocks locations evidence a
  sharp partition of the quiet area in regions of very distinct dynamical
  behavior, highlighting the role of the local magnetic topology in
  structuring the lower chromosphere. The portions of the field of view
  where the photospheric field is very weak, and that are presumably
  connected to distant magnetic structures (or open to the interplanetary
  field), are the site of frequent shock occurrence. On the contrary, in
  regions neighboring the magnetic network and harboring a more horizontal
  configuration of the chromospheric magnetic field, shocks are heavily
  suppressed, even if the photospheric field is essentially absent in
  these areas as well. These latter regions, with much reduced velocity
  power at frequencies of 5.5-8 mHz \citep[the “magnetic shadows” first
  described in][]{gc-judge_01}, are spatially coincident with fibrilar
  structures visible in the Ca II 854.2 line core intensity maps. <P />We
  finally argue that areas within and immediately surrounding the magnetic
  network also display evidence of chromospheric shocks, but occurring at
  periodicities of 4-6 minutes. Such slow shocks are stronger than those
  occurring in field-free areas, as evidenced by the strong emission
  in the inner blue-wing of the line. This is in agreement with recent
  results claiming that magneto-acoustic shocks can develop in inclined
  magnetic structures, acting as `portals' through which the powerful
  low-frequency photospheric oscillations can leak into the chromosphere.

---------------------------------------------------------
Title: Comparison of Ca II K and Ca II 8542 Å Images
Authors: Reardon, K. P.; Cauzzi, G.; Rimmele, T.
2007ASPC..368..151R    Altcode:
  We compare a time sequence of filtergrams obtained in the Ca II K line
  with a series of spectrally resolved images obtained simultaneously
  with the IBIS instrument in the Ca II 8542 Å line. Using the
  narrowband IBIS images and a synthetic filter profile, we construct
  simulated 8542 filtergrams that mimic the observed K<SUB>2V</SUB>
  filtergrams. We observe that these filtergrams appear to contain
  elements corresponding to both photospheric and chromospheric
  structures. Intermediate scale patterns seen in the filtergrams may
  simply be the result of the combination of a variety of structures
  from different atmospheric levels. We analyze the Fourier power
  spectra of the filtergrams and note that at frequencies well above
  the acoustic cut-off value the observed power in the K<SUB>2V</SUB>
  filtergrams seems to be predominantly photospheric in origin. The use
  of Ca II H and K filtergrams to study the chromospheric behavior thus
  may be inherently problematic. Narrowband images in the Ca II 8542 Å
  line might provide a better source of information about chromospheric
  behavior with little loss in spatial or temporal resolution.

---------------------------------------------------------
Title: Commission 12: Solar Radiation &amp; Structure
Authors: Bogdan, Thomas. J.; Martínez Pillet, Valentin; Asplund,
   M.; Christensen-Dalsgaard, J.; Cauzzi, G.; Cram, L. E.; Dravins, D.;
   Gan, W.; Henzl, P.; Kosovichev, A.; Mariska, J. T.; Rovira, M. G.;
   Venkatakrishnan, P.
2007IAUTA..26...89B    Altcode:
  Commission 12 covers research on the internal structure and dynamics
  of the Sun, the "quiet" solar atmosphere, solar radiation and its
  variability, and the nature of relatively stable magnetic structures
  like sunspots, faculae and the magnetic network. There is considerable
  productive overlap with the other Commissions of Division II as
  investigations move progressively toward the fertile intellectual
  boundaries between traditional research disciplines. In large part,
  the solar magnetic field provides the linkage that connects these
  diverse themes. The same magnetic field that produces the more subtle
  variations of solar structure and radiative output over the 11 yr
  activity cycle is also implicated in rapid and often violent phenomena
  such as flares, coronal mass ejections, prominence eruptions, and
  episodes of sporadic magnetic reconnection.The last three years have
  again brought significant progress in nearly all the research endeavors
  touched upon by the interests of Commission 12. The underlying causes
  for this success remain the same: sustained advances in computing
  capabilities coupled with diverse observations with increasing levels
  of spatial, temporal and spectral resolution. It is all but impossible
  to deal with these many advances here in anything except a cursory and
  selective fashion. Thankfully, the Living Reviews in Solar Physics; has
  published several extensive reviews over the last two years that deal
  explicitly with issues relevant to the purview of Commission 12. The
  reader who is eager for a deeper and more complete understanding of
  some of these advances is directed to http://www.livingreviews.org
  for access to these articles.

---------------------------------------------------------
Title: Solar atmospheric oscillations and the chromospheric magnetic
    topology
Authors: Vecchio, A.; Cauzzi, G.; Reardon, K. P.; Janssen, K.;
   Rimmele, T.
2007A&A...461L...1V    Altcode: 2006astro.ph.11206V
  Aims:We investigate the oscillatory properties of the quiet solar
  chromosphere in relation to the underlying photosphere, with particular
  regard to the effects of the magnetic topology. <BR />Methods: For the
  first time we perform a Fourier analysis on a sequence of line-of-sight
  velocities measured simultaneously in a photospheric (Fe I 709.0 nm)
  and a chromospheric line (Ca II 854.2 nm). The velocities were obtained
  from full spectroscopic data acquired at high spatial resolution with
  the Interferometric BIdimensional Spectrometer (IBIS). The field of
  view encompasses a full supergranular cell, allowing us to discriminate
  between areas with different magnetic characteristics. <BR />Results: We
  show that waves with frequencies above the acoustic cut-off propagate
  from the photosphere to upper layers only in restricted areas of
  the quiet Sun. A large fraction of the quiet chromosphere is in fact
  occupied by “magnetic shadows”, surrounding network regions, that
  we identify as originating from fibril-like structures observed in
  the core intensity of the Ca II line. We show that a large fraction
  of the chromospheric acoustic power at frequencies below the acoustic
  cut-off, residing in the proximity of the magnetic network elements,
  directly propagates from the underlying photosphere. This supports
  recent results arguing that network magnetic elements can channel
  low-frequency photospheric oscillations into the chromosphere, thus
  providing a way to input mechanical energy in the upper layers.

---------------------------------------------------------
Title: Reversed granulation in Fe I 7090.4Å
Authors: Janssen, K.; Cauzzi, G.
2007msfa.conf..135J    Altcode:
  The reversal of the photospheric continuum intensity pattern is
  predicted by numerical simulations and has been observed in the wings of
  chromospheric lines. Here we present reversed granulation extracted from
  the photospheric Fe I 7090.4 Å line core intensities, after taking into
  account the velocity effects, in high spatial, spectral and temporal
  resolution. We study correlations with the underlying continuum in terms
  of smoothing, time delays and the temporal evolution. The latter appears
  to be superimposed with an oscillatory signal, that might suggest the
  presence of gravity waves in the observed mid-photospheric layers.

---------------------------------------------------------
Title: IBIS: Reversed Granulation in the Quiet Photosphere
Authors: Janssen, K.; Cauzzi, G.
2006ASPC..354...49J    Altcode:
  The phenomenon of “reversed granulation”, i.e. the partial reversal
  of the intensity pattern occurring in the low photosphere, is predicted
  by numerical simulations and mostly observed in the extended wings
  of chromospheric lines. In this contribution we present high spatial
  resolution 2D maps of the reversed granulation, obtained from line
  core images of the photospheric Fe I 7090.4 Å line, as well as the
  temporal evolution of their correlation with continuum maps, that
  suggests the presence of gravity waves in the mid-photosphere.

---------------------------------------------------------
Title: High-resolution IBIS Observations and Comparison with 3D
    Simulations
Authors: Cauzzi, G.; Asensio Ramos, A.; Reardon, K.; Janssen, K.
2006ASPC..354...26C    Altcode:
  We present first comparisons between high resolution observations of
  the quiet photosphere, obtained with the Interferometric BIdimensional
  Spectrometer (IBIS) in the non-magnetic Fe I 7090.4 Å spectral
  line, and the synthetic spectrum calculated for a 3D snapshot of a
  radiation-hydrodynamical simulation of the solar atmosphere. Together
  with morphological comparisons between the synthetic images and the
  observed ones at different wavelengths, we have carried out comparisons
  between several observables. The simulations reproduce quite well
  many of the observational properties of the high resolution IBIS data,
  apart from the velocity distribution, that contains values quite larger
  than observed.

---------------------------------------------------------
Title: Dynamics and evolution of an eruptive flare
Authors: Teriaca, L.; Falchi, A.; Falciani, R.; Cauzzi, G.;
   Maltagliati, L.
2006A&A...455.1123T    Altcode: 2009arXiv0903.0232T
  Aims.We study the dynamics and the evolution of a C2.3 two-ribbon
  flare, developed on 2002 August 11, during the impulsive phase
  as well as during the long gradual phase. To this end we obtained
  multiwavelength observations using the CDS spectrometer aboard SOHO,
  facilities at the National Solar Observatory/Sacramento Peak, and the
  TRACE and RHESSI spacecrafts.<BR /> Methods: .CDS spectroheliograms
  in the Fe xix, Fe xvi, O v and He i lines allow us to determine the
  velocity field at different heights/temperatures during the flare
  and to compare them with the chromospheric velocity fields deduced
  from Hα image differences. TRACE images in the 17.1 nm band greatly
  help in determining the morphology and the evolution of the flaring
  structures.<BR /> Results: .During the impulsive phase a strong
  blue-shifted Fe xix component (-200 km s<SUP>-1</SUP>) is observed at
  the footpoints of the flaring loop system, together with a red-shifted
  emission of O v and He i lines (20 km s<SUP>-1</SUP>). In one footpoint
  simultaneous Hα data are also available and we find, at the same time
  and location, downflows with an inferred velocity between 4 and 10 km
  s<SUP>-1</SUP>. We also verify that the "instantaneous" momenta of the
  oppositely directed flows detected in Fe xix and Hα are equal within
  one order of magnitude. These signatures are in general agreement with
  the scenario of explosive chromospheric evaporation. Combining RHESSI
  and CDS data after the coronal upflows have ceased, we prove that,
  independently from the filling factor, an essential contribution to
  the density of the post-flare loop system is supplied from evaporated
  chromospheric material. Finally, we consider the cooling of this loop
  system, that becomes successively visible in progressively colder
  signatures during the gradual phase. We show that the observed cooling
  behaviour can be obtained assuming a coronal filling factor of ≈0.2
  to 0.5.<BR />

---------------------------------------------------------
Title: The Interferometric Bidimensional Spectrometer (IBIS)
Authors: Cauzzi, Gianna; Cavallini, F.; Reardon, K.; Berrilli, F.;
   Rimmele, T.; IBIS Team
2006SPD....37.0608C    Altcode: 2006BAAS...38..226C
  The Interferometric Bidimensional Spectrometer (IBIS) is an advanced
  instrument for imaging spectroscopy installed at the Dunn Solar
  Telescope at NSO/Sacramento Peak. The instrument has been constructed by
  a consortium of italian institutes and allows for observations of the
  photosphere and chromosphere at high spatial, spectral, and temporal
  resolution. Such observations are essential for performing spatial
  and spectral comparisons with numerical simulations. We will present
  some of the performance characteristics of the instrument and show some
  examples of the IBIS data. We will also show some initial results of the
  recently tested polarimetric mode. IBIS is available for community use
  as a facility instrument of NSO.IBIS has been funded by the Italian
  Research Ministry (MIUR), the Italian Institute for Astrophysics
  (INAF), and the Universities of Florence and Rome. Additional support
  is provided by the National Solar Observatory.

---------------------------------------------------------
Title: Dynamics of the solar photosphere with IBIS. I. Reversed
    intensity structure in the mid-photosphere
Authors: Janssen, K.; Cauzzi, G.
2006A&A...450..365J    Altcode:
  Context: .We investigate the quiet solar photosphere with the new
  Interferometric BI-dimensional Spectrometer (IBIS), recently installed
  at the Dunn Solar Telescope of the National Solar Observatory,
  Sacramento Peak, NM.<BR /> Aims: . We study the occurrence of reverse
  granulation in the mid-photosphere, and its properties.<BR /> Methods:
  . IBIS, a double Fabry-Perot system with a narrow passband of 20 mÅ
  at 6000 Å was used to acquire a one hour sequence of 2D scans in
  the photospheric Fe I 7090.4 Å and Fe II 7224.5 Å lines, and in the
  chromospheric Ca II 8542 Å line. Photospheric velocities are measured
  for statistical study. To visualize the reversed intensity structure,
  the influence of velocity on the steep photospheric profiles is taken
  into account. The correlation between mid-photospheric intensities and
  continuum is then studied, considering the effects of spatial smoothing
  and time delay. The temporal evolution of the cross-correlation
  coefficients is analyzed. <BR /> Results: . The distribution of
  photospheric velocities is consistent with values in the literature,
  thus confirming the reliability of the instrument for this kind of
  study. "Reversed granulation" is clearly visible in the Fe I 7090.4 Å
  line center, formed at about 200 km. It provides a weak anti-correlation
  with the continuum, as expected from numerical simulations. Images
  acquired in the far wings of the Ca II line display the same pattern
  with a slightly higher correlation. In both cases a spatial smoothing
  larger than 0.5” decreases the level of anti-correlation, while a
  time delay of about 2 min increases it. Together, these facts suggest
  that the phenomenon is mainly due to a reversal of temperature
  fluctuations between granules and intergranules, occurring in the
  mid-photosphere. The temporal evolution of the anti-correlation between
  the Fe I line center and the continuum reveals a clear oscillatory
  signal that we consider as highly suggestive of the presence of gravity
  waves developing from the mid-photosphere outwards.<BR />

---------------------------------------------------------
Title: High-resolution IBIS Observations and Comparison with 3D
    Simulations .
Authors: Asensio Ramos, A.; Janssen, K.; Cauzzi, G.; Reardon, K.
2006MSAIS...9...59A    Altcode:
  High resolution observations of a very quiet region of the solar
  surface have been obtained with IBIS (Interferometric BIdimensional
  Spectrometer) in the non-magnetic Fe I 7090.4 Å spectral line. We
  present a first comparison between the observed, spatially resolved,
  spectral data and the simulated spectra in a 3D snapshot of a
  radiation-hydrodynamical simulation of the solar atmosphere. Preliminary
  results indicate that the simulations reproduce quite well many of
  the observational properties of the high resolution IBIS data, even
  though the simulations present a velocity distribution that contains
  values quite larger than the observed ones.

---------------------------------------------------------
Title: Quiet Solar Photosphere: Comparisons of High Resolution
    Observations with 3-D Simulations
Authors: Cauzzi, G.; Asensio Ramos, A.; Reardon, K.; Janssen, K.
2005ESASP.600E..12C    Altcode: 2005dysu.confE..12C; 2005ESPM...11...12C
  No abstract at ADS

---------------------------------------------------------
Title: Helium line formation in a solar active region
Authors: Mauas, P. J. D.; Andretta, V.; Falchi, A.; Falciani, R.;
   Teriaca, L.; Cauzzi, G.
2005ESASP.560..811M    Altcode: 2005csss...13..811M
  No abstract at ADS

---------------------------------------------------------
Title: Helium Line Formation and Abundance in a Solar Active Region
Authors: Mauas, P. J. D.; Andretta, V.; Falchi, A.; Falciani, R.;
   Teriaca, L.; Cauzzi, G.
2005ApJ...619..604M    Altcode: 2004astro.ph.12058M
  An observing campaign (SOHO JOP 139), coordinated between ground-based
  and Solar and Heliospheric Observatory (SOHO) instruments, has been
  planned to obtain simultaneous spectroheliograms of the same active
  region in several spectral lines. The chromospheric lines Ca II K,
  Hα, and Na I D, as well as He I 10830, 5876, 584, and He II 304 Å
  lines have been observed. The EUV radiation in the range λ&lt;500
  Å and in the range 260&lt;λ&lt;340 Å has also been measured at
  the same time. These simultaneous observations allow us to build
  semiempirical models of the chromosphere and low transition region of
  an active region, taking into account the estimated total number of
  photoionizing photons impinging on the target active region and their
  spectral distribution. We obtained a model that matches very well all
  the observed line profiles, using a standard value for the He abundance
  ([He]=0.1) and a modified distribution of microturbulence. For this
  model we study the influence of the coronal radiation on the computed
  helium lines. We find that, even in an active region, the incident
  coronal radiation has a limited effect on the UV He lines, while it
  is of fundamental importance for the D3 and 10830 Å lines. Finally,
  we build two more models, assuming values of He abundance [He]=0.07 and
  1.5, only in the region where temperatures are &gt;1×10<SUP>4</SUP>
  K. This region, between the chromosphere and transition region, has been
  indicated as a good candidate for processes that might be responsible
  for strong variations of [He]. The set of our observables can still be
  well reproduced in both cases, changing the atmospheric structure mainly
  in the low transition region. This implies that, to choose between
  different values of [He], it is necessary to constrain the transition
  region with different observables, independent of the He lines.

---------------------------------------------------------
Title: Overview of AN Eruptive Flare: from Chromospheric Evaporation
    to Cooling of Hot Flaring Loops
Authors: Teriaca, L.; Maltagliati, L.; Falchi, A.; Falciani, R.;
   Cauzzi, G.
2004ESASP.575..265T    Altcode: 2004soho...15..265T
  No abstract at ADS

---------------------------------------------------------
Title: IBIS Observations of Quiet Sun Photosphere - Velocity Structure
    from Fe I 7090.4 Å
Authors: Janßen, Katja; Cauzzi, Gianna; Falchi, Ambretta; Cavallini,
   Fabio; Reardon, Kevin
2004IAUS..223..631J    Altcode: 2005IAUS..223..631J
  In our contribution we introduce the new Interferometric BIdimensional
  Spectrometer (IBIS) and present the first results on bisector velocities
  of two dimensional spectral scans in FeI 7090.4 Å comparing granules
  and intergranular regions.

---------------------------------------------------------
Title: Solar and Heliospheric Observatory/Coronal Diagnostic
Spectrograph and Ground-based Observations of a Two-Ribbon Flare:
    Spatially Resolved Signatures of Chromospheric Evaporation
Authors: Teriaca, L.; Falchi, A.; Cauzzi, G.; Falciani, R.; Smaldone,
   L. A.; Andretta, V.
2003ApJ...588..596T    Altcode:
  During a coordinated observing campaign (Solar and Heliospheric
  Observatory, SOHO JOP 139), we obtained simultaneous spectroheliograms
  of a solar active region in several spectral lines, sampling levels
  from the chromosphere to the corona. Ground-based spectroheliograms
  were acquired at the Dunn Solar Tower of the National Solar
  Observatory/Sacramento Peak in four chromospheric lines, while the
  coronal diagnostic spectrograph on board SOHO was used to obtain
  rasters of the active region in transition region (TR) and coronal
  lines. Such a complete data set allowed us to compare the development
  of intensity and velocity fields during a small two-ribbon flare
  in the whole atmosphere. In particular, we obtained for the first
  time quasi-simultaneous and spatially resolved observations of
  velocity fields during the impulsive phase of a flare, in both the
  chromosphere and upper atmosphere. In this phase, strong downflows
  (up to 40 km s<SUP>-1</SUP>) following the shape of the developing
  ribbons are measured at chromospheric levels, while strong upward
  motions are instead measured in TR (up to -100 km s<SUP>-1</SUP>)
  and coronal lines (-160 km s<SUP>-1</SUP>). The spatial pattern of
  these velocities have a common area about 10" wide. This is the first
  time that opposite-directed flows at different atmospheric levels
  are observed in the same spatial location during a flare. These
  signatures are highly suggestive of the chromospheric evaporation
  scenario predicted in theoretical models of flares.

---------------------------------------------------------
Title: Mass Motions in a Young Active Region
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.
2003MmSAI..74..659C    Altcode:
  We present an observational program devoted to the study of dynamic
  phenomena at small spatial and temporal scales throughout the solar
  atmosphere, with special attention to chromospheric events that have
  an impact on the coronal structure. On the one hand, we show the
  existence of flare signatures in the chromosphere at the smallest
  scales, supporting the idea that (micro)flares represent a viable
  mechanism for supply of heat and mass to the corona. On the other,
  such events are quite scarce in our dataset, while much more common
  are surge-like events, occurring repeatedly in the same locations
  and visible both in the chromosphere and the corona, and that do not
  display obvious flare signatures.

---------------------------------------------------------
Title: Spatially resolved signatures of chromospheric evaporation
    during a small two-ribbon flare
Authors: Teriaca, L.; Falchi, A.; Cauzzi, G.; Falciani, R.; Smaldone,
   L. A.; Andretta, V.
2003MmSAI..74..635T    Altcode:
  Ground based spectroheliograms of a solar active region were acquired
  in four chromospheric lines simultaneously with rasters in transition
  region (TR) and coronal lines obtained with the Coronal Diagnostic
  Spectrograph (CDS) aboard SOHO. Such a complete dataset allows us to
  study the development of intensity and velocity fields during a small
  two-ribbon flare in the whole atmosphere. In particular, we obtain for
  the first time quasi-simultaneous and spatially resolved observations
  of velocity fields during the impulsive phase of a flare, both in
  chromosphere and upper atmosphere. In this phase, strong downflows
  (up to 40 km s<SUP>-1</SUP>) following the shape of the developing
  ribbons are measured at chromospheric levels, while strong upward
  motions are measured in TR (up to -100 km s<SUP>-1</SUP>) and coronal
  lines (-160 km s<SUP>-1</SUP>). The spatial pattern of these velocities
  have a common area about 10 arcsec wide. This is the first time that
  opposite directed flows at different atmospheric levels are observed
  in the same spatial location during a flare. These signatures are
  highly suggestive of the chromospheric evaporation scenario predicted
  in theoretical models of flares.

---------------------------------------------------------
Title: Chromospheric and Transition region He lines during a flare
Authors: Falchi, A.; Mauas, P. J. D.; Andretta, V.; Teriaca, L.;
   Cauzzi, G.; Falciani, R.; Smaldone, L. A.
2003MmSAI..74..639F    Altcode:
  An observing campaign (SOHO JOP 139), coordinated between ground
  based and SOHO instruments, has been planned to obtain simultaneous
  spectroheliograms of the same area in several spectral lines. The
  chromospheric lines Ca II K, Hα and Na I D as well as He I 10830,
  5876, 584 and 304 Ålines have been observed. These observations allow
  us to build semi-empirical models of the atmosphere before and during
  a small flare. With these models, constructed to match the observed
  line profiles, we can test the He abundance value.

---------------------------------------------------------
Title: Chromospheric evaporation in a two-ribbon flare
Authors: Cauzzi, G.; Falchi, A.; Teriaca, L.; Falciani, R.; Smaldone,
   L. A.; Andretta, V.
2002ESASP.506..561C    Altcode: 2002ESPM...10..561C; 2002svco.conf..561C
  We present simultaneous, spatially and temporally resolved
  chromospheric, transition region and coronal observations of a small
  eruptive flare studied throughout its whole development. We show
  that strong and co-spatial plasma motions, oppositely directed in the
  chromosphere (downflows) and in upper atmospheric layers (upflows),
  develop at the onset of the flare. For the first time, we prove that
  such oppositely directed flows originate from the same flaring kernels
  in different atmospheric layers. Using realistic values for the plasma
  parameters in the flaring loop, we also estimate a balance between
  the upward and downward momenta. Our observations confirm in a very
  convincing way the scenario of chromospheric evaporation predicted in
  theoretical models of flares.

---------------------------------------------------------
Title: Combined space and ground based observations of a C-1 flare
Authors: Teriaca, L.; Falchi, A.; Cauzzi, G.; Falciani, R.; Smaldone,
   L. A.; Andretta, V.
2002ESASP.508..457T    Altcode: 2002soho...11..457T
  We present temporally and spatially resolved space and ground based
  observations of a C1 flare. Ground based spectroheliograms were acquired
  at the Dunn Solar Tower of NSO/Sacramento Peak in several chromospheric
  lines. Simultaneously, the Coronal Diagnostic Spectrograph (CDS)
  aboard SoHO was used to obtrain rasters of the same active region
  in transiton region (TR) and coronal lines. This unique dataset
  provides us, for the first time, with spatially resolved observations
  of velocity fields during the impulsive phase of the flare, from the
  chromosphere up to the TR and the corona. At the time of the emission
  peak, a large area of the flaring kernel observed in TR lines is
  characterized by upward velocities. A ~6"×6" kernel displays upflows
  velocity above 80 km s<SUP>-1</SUP>. In this same area we found, in
  data obtained about 3 minutes later, chromospheric downflows of 10 -
  20 km s<SUP>-1</SUP>. This is the first time that opposite directed
  flows at different atmospheric levels are observed in the same spatial
  location during a flare.

---------------------------------------------------------
Title: Introduction (JOSO Annual Report 2000/2001)
Authors: Cauzzi, G.
2002joso.book....1C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Minutes of the 33rd JOSO Board Meeting - 2001
Authors: Cauzzi, G.; Kucera, A.; Schmieder, B.
2002joso.book...15C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: European Solar Magnetism Network
Authors: Cauzzi, G.
2002joso.book....8C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Minutes of the 32nd JOSO Board Meeting - 2000
Authors: Cauzzi, G.; Kucera, A.; Schmieder, B.
2002joso.book...10C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Search for Microflaring Activity in the Magnetic Network
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.
2001SoPh..199...47C    Altcode: 2000astro.ph.11433C
  We analyze the temporal behavior of network bright points (NBPs)
  searching for low-atmosphere signatures of flares occurring
  on the magnetic network. We make use of a set of data acquired
  during coordinated observations between ground-based observatories
  (NSO/Sacramento Peak) and the MDI instrument on board SOHO. Light curves
  in chromospheric spectral lines show only small-amplitude temporal
  variations, without any sudden intensity enhancement that could suggest
  the presence of a transient phenomenon such as a (micro)flare. Only
  one NBP shows spikes of downward velocity, of the order of 2-4 km
  s<SUP>−1</SUP>, considered as signals of compression associated with
  a (micro)flare occurrence. For this same NBP, we also find a peculiar
  relationship between the magnetic and velocity fields fluctuations,
  as measured by MDI. Only for this point the B−V fluctuations
  are well correlated, suggesting the presence of magneto-acoustic
  waves propagating along the magnetic structure. This correlation is
  lost during the compression episodes and resumes afterward. An A6
  GOES soft X-ray burst is temporally associated with the downward
  velocity episodes, suggesting that this NBP is the footpoint of a
  flaring loop. This event has a total thermal energy content of about
  10<SUP>28</SUP> erg, and, hence, belongs to the microflare class.

---------------------------------------------------------
Title: Network and internetwork properties at photospheric and
    chromospheric levels
Authors: Falchi, A.; Cauzzi, G.; Falciani, R.
2001MmSAI..72..549F    Altcode:
  We use coordinated observations between ground-based observatories
  (NSO/Sacramento Peak) and the Michelson Doppler Interferometer onboard
  SOHO to analyze the characteristics of Network Bright Points (NBPs)
  at different atmospheric heights and compare them with those of the
  surrounding internetwork areas. We improve on the existing statistics
  using a sample of 11 NBPs, and the same number of "test" internetwork
  areas, defined in a comparable way. The method we adopted to study
  the temporal evolution of NBPs insures that each bright structure is
  properly followed in time and position at each height.

---------------------------------------------------------
Title: Network and internetwork: a compared multiwavelength analysis
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.
2000A&A...357.1093C    Altcode: 2000astro.ph..4082C
  We analyze the temporal behavior of Network Bright Points (NBPs)
  using a set of data acquired during coordinated observations between
  ground-based observatories (mainly at the NSO/Sacramento Peak) and
  the Michelson Doppler Interferometer onboard SOHO. We find that, at
  any time during the observational sequence, all the NBPs visible in
  the NaD_2 images are co-spatial within 1<SUP>”</SUP> with locations
  of enhanced magnetic field. The “excess” of NaD_2 intensity in NBPs,
  i.e. the emission over the average value of quiet regions, is directly
  related to the magnetic flux density. This property implies that, in
  analogy with the Ca II K line, the NaD_2 line center emission can be
  used as a proxy for magnetic structures. We also compare the oscillation
  properties of NBPs and internetwork areas. At photospheric levels no
  differences between the two structures are found in power spectra,
  but analysis of phase and coherence spectra suggests the presence
  of downward propagating waves in the internetwork. At chromospheric
  levels some differences are evident in the power spectrum between
  NBPs and internetwork. At levels contributing to the NaD_2 emission
  the NBPs show a strongly reduced amplitude of oscillations at the p -
  mode frequencies. At levels contributing to the Hα \ core emission,
  the amplitude of network oscillations is higher than the internetwork
  ones. The power spectrum of NBPs at this wavelength shows an important
  peak at 2.2 mHz (7 minutes), not present in the internetwork areas. Its
  coherence spectrum with Hα \ wings shows very low coherence at this
  frequency, implying that the oscillations at these chromospheric levels
  are not directly coupled with those present in lower layers.

---------------------------------------------------------
Title: Is Flaring Activity present in the Chromospheric Network ?
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Vial, J. C.
1999ESASP.448..685C    Altcode: 1999mfsp.conf..685C; 1999ESPM....9..685C
  Microflares occurring at coronal levels are one of the mechanisms
  proposed for the heating and dynamics of the chromospheric
  network. During a SOHO coordinated campaign, we acquired a set
  of chromospheric and transition region data, at high temporal and
  spatial resolution, that are suitable for such a research. We describe
  the characteristics of network points at several heights in the
  atmosphere. We look for the presence of signatures typical of flares,
  albeit at much smaller scales. Only one, of the 11 network points
  analyzed over 1 hr of observations, displays several episodes of red
  asymmetry in the H_α wings. These asymmetries can be interpreted
  as downward motions induced by the sudden compression of the lower
  atmosphere caused by either a particle beam or a conduction front. The
  analysis hence suggests that microflaring events in network points
  have a low occurrence probability, or that their energy flux is still
  below our observational capabilities.

---------------------------------------------------------
Title: Wavelet Analysis of Spatial Coherent Structures in the
    Photosphere
Authors: Pietropaolo, E.; Berrilli, F.; Consolini, G.; Smaldone,
   L. A.; Straus, T.; Cauzzi, G.; Bruno, R.; Bavassano, B.
1999ESASP.448..343P    Altcode: 1999ESPM....9..343P; 1999mfsp.conf..343P
  No abstract at ADS

---------------------------------------------------------
Title: Multiwavelength Analysis of Network Bright Points - Coordinated
    Observations SOHO-GBO JOP No 37
Authors: Falchi, A.; Cauzzi, G.; Falciani, R.; Vial, J. -C.
1999ASPC..184..261F    Altcode:
  We analyze the temporal behaviour of Network Bright Points (NBPs)
  using a set of data acquired during coordinated observations between
  ground based observatories (mainly at the NSO/Sacramento Peak) and the
  SUMER and MDI instruments onboard SOHO. We find that, at any time,
  all NBPs present in the NaD_2 images are co-spatial within 1" with
  locations of enhanced magnetic field density, and that not all the
  NBPs identified in the low chromosphere can be identified at higher
  levels. We calculate the intensity power spectrum for each NBP in
  several low-chromospheric signatures, such as the red wing of Hα,
  NaD_2 and Hα line center. The power spectra show no power at the 5.5
  mHz frequency, while they display an enhancement at frequencies below
  2 mHz, corresponding to periods between 8 and 20 minutes.

---------------------------------------------------------
Title: Asymmetric Magnetic Field Distribution in Active Regions
Authors: Cauzzi, Gianna; van Driel-Gesztelyi, Lidia
1998ASPC..140..105C    Altcode: 1998ssp..conf..105C
  No abstract at ADS

---------------------------------------------------------
Title: Properties of solar granulation cells in quiet regions as
    derived from a time series of white light images
Authors: Cauzzi, G.; Consolini, G.; Berrilli, F.; Smaldone, L. A.;
   Straus, T.; Bavassano, B.; Bruno, R.; Caccin, B.; Carbone, V.; Egidi,
   A.; Ermolli, I.; Florio, A.; Pietropaolo, E.
1998MmSAI..69..647C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Chromospheric evidence for magnetic reconnection in a
    two-ribbon flare.
Authors: Falchi, A.; Qiu, J.; Cauzzi, G.
1998joso.proc..149F    Altcode:
  The authors study a two-ribbon flare, observed with both ground and
  satellite-based instruments. The most important result of their study
  is given by the measure of the chromospheric downflows within several
  flaring kernels, heated by a conduction front from the corona. In all
  the cases examined, they find a stronger downflow at the outer edge
  of the flaring ribbon, on a region only a few arcsec across. They
  think that these observations provide a clear evidence of magnetic
  reconnection. As explicitly show in recent flare models that consider
  heat conduction from the reconnecting site, the conduction front
  directly maps only the outer boundary magnetic field lines of the
  reconnecting loops. Its effect on the chromospheric layers would be
  to compress the plasma, triggering downflows only on the outer edge
  on the ribbons, consistently with the authors' observations.

---------------------------------------------------------
Title: Chromospheric evidence for magnetic reconnection
Authors: Falchi, A.; Qiu, J.; Cauzzi, G.
1997A&A...328..371F    Altcode:
  We study the decay phase of an M2.6 flare, observed with ground
  based instruments at NSO/Sac Peak and with the cluster of instruments
  onboard Yohkoh. The whole set of chromospheric and coronal data gives a
  picture consistent with the classical Kopp-Pneuman model of two-ribbon
  flares. We clearly witness new episodes of coronal energy release, most
  probably due to magnetic reconnection, during the decaying phase of
  the flare. Within the newly created chromospheric ribbons, we identify
  several small kernels, footpoints of magnetic loops involved in the
  flare, where energy is probably deposited by a conduction front from
  coronal sources. The presence of a source (T_e=22 MK, and EM=5.x 10(48)
  cm(-3) ) thermally emitting in the 14-23 keV energy band confirms this
  hypothesis. A new, interesting observational result is given by the
  measure of chromospheric downflows in different parts of the flaring
  kernels. For all the cases examined, we find a stronger downflow at
  the outer edge of the flaring structure. The flows have amplitude of
  tens of km \ s(-1) , over regions only a few arcsec across, and seem
  to decrease when the flaring kernels slow their motion on the solar
  surface and fade away. We believe that these downflows directly map
  the outer boundary magnetic field lines of the reconnecting loops,
  as predicted in recent reconnection models that take into account
  explicity the effects of heat conduction. The flows represent the
  chromospheric counterpart of coronal features observed in soft X-ray
  such as cusp-like structures and the temperature stratification in
  flaring loop systems. The observed amplitude of these chromospheric
  flows could be an important constraint for quantitative modelling of
  coronal reconnection mechanisms and their effects on the lower solar
  atmosphere.

---------------------------------------------------------
Title: The Magneto-Optical Filter in Napoli: Perspectives and Test
    Observations
Authors: Moretti, P. F.; Severino, G.; Cauzzi, G.; Reardon, K.;
   Straus, T.; Cacciani, A.; Marmolino, C.; Oliviero, M.; Smaldone, L. A.
1997ASSL..225..293M    Altcode: 1997scor.proc..293M
  An observing station based on the Magneto-Optical-Filter (MOF)
  technology is being installed at Osservatorio Astronomico di
  Capodimonte, in Napoli. In this paper, the main characteristics and
  goals of this new instrument are discussed, and several velocity and
  magnetic observations from a test campaign are shown.

---------------------------------------------------------
Title: Magnetic reconnection driven by emergence of sheared magnetic
    field.
Authors: Schmieder, B.; Aulanier, G.; Demoulin, P.; van
   Driel-Gesztelyi, L.; Roudier, T.; Nitta, N.; Cauzzi, G.
1997A&A...325.1213S    Altcode:
  Recurrent subflares (Class C) were observed in the NOAA 7608 active
  region on 27 October 1993. From multi-wavelength observations
  (white-light, magnetic field, H-alpha, X-ray), obtained during a
  coordinated campaign between Pic du Midi and Yohkoh, it appears that
  these flares were double ribbon flares caused by new flux emergence. As
  the flare begins, the X-ray emission observed with Yohkoh/SXT is
  loop-shaped with the axis almost parallel to the magnetic inversion
  line, while during the flare development, X-ray loops appear at the
  location of the emerging flux. The extrapolation of the photospheric
  magnetic field in a linear force-free field configuration allows
  identification of the magnetic configuration given by the flares. The
  Hα flare ribbons are located at the intersections of the computed
  quasi-separatrice layers (QSLs) with the chromosphere. We show that
  the initial loop-shaped X-ray emission region is in fact formed by
  several smaller loops directed in a nearly orthogonal direction with
  their feet anchored close to or in the Hα ribbons. During the flare
  development there are X-ray loops which represent only one foot of
  open or largescale magnetic loops. For the studied flares the puzzling
  soft X-rays observations could only be understood with the help of Hα
  and magnetic data combined with a modeling of the coronal magnetic
  field. Further, from the deduced magnetic field topology, the width
  of the QSLs and our present knowledge of 3-D magnetic reconnection,
  we conclude that the flare was due to magnetic reconnection driven
  by emergence of sheared magnetic field impacting in the pre-existing
  coronal field.

---------------------------------------------------------
Title: Multispectral Observations of AN Eruptive Flare
Authors: Qiu, J.; Falchi, A.; Falciani, R.; Cauzzi, G.; Smaldone, L. A.
1997SoPh..172..171Q    Altcode: 1997ESPM....8..171Q
  We analyze the pre-flare and impulsive phase of an eruptive (two-ribbon)
  flare at several wavelengths. The total energy (mechanical plus
  radiative) released by the flare is 8 x 10<SUP>30</SUP> erg, about a
  factor 6 higher than the free magnetic energy (1.3 10<SUP>30</SUP> erg)
  estimated from the non-potentiality of the magnetic field configuration
  in the flare area. During the impulsive phase, we find a very good time
  coincidence between the hard X-ray light curve and the light curves
  for 2 small areas (≃ 4″ in size) in the red wing of the Hα line
  and in the He-D<SUB>3</SUB> line center. This temporal coincidence is
  compatible with the interpretation that hard X-ray emission is produced
  by bremsstrahlung of accelerated electron beams striking these dense
  areas. For the other regions of the Hα ribbons we find more gradual
  light curves, suggesting a different energy transport mechanism such
  as conduction.

---------------------------------------------------------
Title: Dynamics of Minor Solar Activity \newline Coordinated
    Observations SOHO-GBO JOP #37
Authors: Cauzzi, G.; Vial, J. C.; Falciani, R.; Falchi, A.; Smaldone,
   L. A.
1997ASPC..118..309C    Altcode: 1997fasp.conf..309C
  We present a program for coordinated observations between ground based
  observatories, mainly NSO/Sacramento Peak, and several instruments
  onboard SOHO (primarily SUMER). The scientific goal is the study of
  small activity phenomena, at high spatial and temporal resolution.

---------------------------------------------------------
Title: Preface
Authors: Cauzzi, G.; Marmolino, C.
1997MmSAI..68..359C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: East-West inclination of field lines in active regions
Authors: Cauzzi, G.; van Driel-Gesztelyi, L.
1997MmSAI..68..487C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The inconstant Sun. Proceedings. 2nd Napoli Thinkshop on
    Physics and Astrophysics, Napoli (Italy), 18 Mar 1996.
Authors: Cauzzi, G.; Marmolino, C.
1997MmSAI..68..355C    Altcode:
  This Thinkshop addresses the problem of the contribution that solar
  physics can give to modern physics and astrophysics.

---------------------------------------------------------
Title: ARTHEMIS: The Archive Project for the IPM and THEMIS
Authors: Reardon, K.; Severino, G.; Cauzzi, G.; Gomez, M. T.; Straus,
   T.; Russo, G.; Smaldone, G.; Marmolino, C.
1997ASPC..118..398R    Altcode: 1997fasp.conf..398R
  We describe the plan for ARTHEMIS, the italian archive for THEMIS, from
  the point of view of the prospective users of the archive. This archive
  is designed to store the data from the Italian Panoramic Monochromator
  (IPM) instrument installed on THEMIS as well as the full-disk images
  obtained by the telescope. We break the expected users down into
  seven categories: a) prospective IPM users; b) campaign planners; c)
  data analysts, d) external collaborators; e) instrument monitors, f)
  archival observers; and g) the general public.

---------------------------------------------------------
Title: ARTHEMIS: The archive project for the Italian Panoramic
    Monochromator
Authors: Reardon, K.; Severino, G.; Cauzzi, G.; Gomez, M. T.; Straus,
   T.; Russo, G.; Smaldone, L. A.; Marmolino, C.
1997MmSAI..68..499R    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Li I resonance lines in a solar active region.
Authors: Cauzzi, G.; Gomez, M. T.; Severino, G.
1997joso.proc...57C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: 3D Magnetic Reconnection at an X-Ray Bright Point
Authors: Mandrini, C. H.; Démoulin, P.; Van Driel-Gesztelyi, L.;
   Schmieder, B.; Cauzzi, G.; Hofmann, A.
1996SoPh..168..115M    Altcode:
  On May 1, 1993, a flaring X-ray bright point (XBP) was observed for
  about 16 hours in the old, disintegrating, bipolar active region (AR)
  NOAA 7493. During this period, a minor magnetic bipole (10<SUP>20</SUP>
  Mx) emerged in the region. We have found observational evidence showing
  that the XBP brightenings were due to magnetic reconnection between
  the new bipole and pre-existing plage fields. The aim of the present
  work is to substantiate with magnetic modelling what has been shown
  by the observations. For this purpose we extrapolate the observed
  photospheric magnetic fields in the linear force-free approximation
  and follow its evolution during the lifetime of the XBP. From the
  computed coronal field lines we determine the location of regions of
  drastic change in field-line linkage, called `quasi-separatrix layers'
  or QSLs. QSLs are open layers that behave physically like separatrices:
  the break down of ideal magnetohydrodynamics and the release of free
  magnetic energy may occur at these locations when their thickness
  is small enough. The extrapolated field lines, with photospheric
  footpoints on both sides of QSLs, match the observed chromospheric and
  coronal structures (arch filament system, XBP and faint X-ray loops
  (FXL)). We study also the evolution of the width of the QSL located
  over the new negative polarity pore: the calculated QSL is very thin
  (typically less than 100 m) during the lifetime of the XBP, but becomes
  much thicker (≥ 10<SUP>4</SUP> m) after the XBP has faded. Furthermore
  we show that peaks in X-ray brightness propagate along the FXL with a
  velocity of ≈ 670 km s<SUP>-1</SUP>, starting from the XBP location,
  implying that the energy is released where the emerging bipole impacts
  against pre-existing coronal loops. We discuss the possible mechanism
  of energy transport and conclude that the energy is conducted to the
  remote footpoints of the FXL by a thermal front. These results strongly
  support the supposition that the XBP brightness and flaring are due
  to the interaction of different flux systems, through 3D magnetic
  reconnection, at QSLs.

---------------------------------------------------------
Title: Coordinated observations of solar activity phenomena. II. The
    velocity field pattern in an elementary flare.
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.
1996A&A...306..625C    Altcode:
  We present the line-of-sight velocity pattern determined from spectra
  obtained before and during a small flare, whose emission properties have
  been studied in Cauzzi et al. (1995, Paper I). The flare hard X-ray
  (HXR) emission, in the range 25-100keV, consists of five separate
  and short spikes (lasting 1-7s), which suggests that this flare
  is a sequence of separate elementary bursts. 40 seconds before the
  occurrence of any HXR emission the flare kernel is already bright in
  H<SUB>alpha</SUB>_+1.5A and shows a typical chromospheric flare spectrum
  with Balmer lines in emission up to H_13_. Also, few seconds before
  the impulsive phase of the flare (as marked by the occurrence of the
  first HXR spike) an upward motion is determined from lines originating
  in high chromospheric layers (CaII K and H<SUB>delta</SUB>_) and from
  metallic lines (Si I 3905, Fe I multiplets 4 and 5). These motions
  together with a simultaneous strong emission suggest that the early
  chromospheric modifications, which may be considered as signatures
  of flare precursor, are due to some in situ mechanisms. 6 seconds
  after the peak time of the first HXR spike we determine a downward
  velocity, ranging from 1km/s for the metallic lines up to 20km/s for
  H<SUB>delta</SUB>_ and CaII K lines, for all the points of the slit
  intersecting the H<SUB>alpha</SUB>_+1.5A kernel. According to the known
  dynamic flare models, the measured velocity can be explained either by
  direct heating of the chromosphere from non-thermal electrons with a
  low energy cutoff of 10keV, or by a thermal conduction front from the
  hot corona. The downward velocity continues to increase (roughly by a
  factor of 2) for 10s after the end of the first HXR spike; none of the
  existing models predicts a similar behavior. After the fourth HXR spike
  the direction of the velocity changes over the H<SUB>alpha</SUB>_+1.5 A
  kernel and two small regions (=~3" in size), can be distinguished. In
  the first one a downward velocity of about 15km/s is derived for
  H<SUB>delta</SUB>_ and CaII K lines simultaneously to a velocity
  =~1km/s from the metallic lines. In the second area, the velocities
  derived from H<SUB>delta</SUB>_ and CaII K lines are upward directed,
  with values up to -40km/s, while the velocity derived from the metallic
  lines is still downward directed, with values =~1km/s. The sudden onset
  of an upward motion could be related to the development of a surge
  well visible after the flare; probably only the higher chromospheric
  layers supply material to the surge.

---------------------------------------------------------
Title: Asymmetries in solar active regions and flux emergence models
Authors: Cauzzi, G.; Moreno-Insertis, F.; van Driel-Gesztelyi, L.
1996ASPC..109..121C    Altcode: 1996csss....9..121C
  No abstract at ADS

---------------------------------------------------------
Title: X-Ray Bright Point Flares Due to Magnetic Reconnection
Authors: Van Driel-Gesztelyi, L.; Schmieder, B.; Cauzzi, G.; Mein,
   N.; Hofmann, A.; Nitta, N.; Kurokawa, H.; Mein, P.; Staiger, J.
1996SoPh..163..145V    Altcode:
  Ground-based optical observations coordinated with Yohkoh/SXT X-ray
  observations of an old, disintegrating bipolar active region AR NOAA
  7493 (May 1, 1993) provided a multiwavelength data base to study
  a flaring `active region' X-ray bright point (XBP) of about 16 hr
  lifetime, and the activity related to it in different layers of the
  solar atmosphere. The XBP appeared to be related to a new minor bipole
  of about 10<SUP>20</SUP> Mx. Superposed on a global evolution of soft
  X-ray brightness, the XBP displayed changes of brightness, lasting for
  1-10 min. During the brightenings the XBP apparently had a spatial
  structure, which was (tiny) loop-like rather than point-like. The
  X-ray brightenings were correlated with chromospheric activity: (i)
  brightenings of underlying chromospheric faculae, and (ii) appearance
  of strong turbulent velocities in the arch filament system. We propose
  that the XBP brightenings were due to reconnection of the magnetic
  field lines (sketched in 3D) between the new bipole and a pre-existing
  plage field induced by the motion of one of the new pores (v = 0.2
  km s<SUP>−1</SUP>) towards the plage, and that the XBP itself was
  a reconnected hot loop between them.

---------------------------------------------------------
Title: Simultaneous Observation of Solar Surges in H alpha and X-ray
Authors: Akioka, M.; Cauzzi, G.
1996mpsa.conf..451A    Altcode: 1996IAUCo.153..451A
  No abstract at ADS

---------------------------------------------------------
Title: Minor Photospheric and Chromospheric Magnetic Activity and
    Related Coronal Signatures
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Hiei, E.; Smaldone,
   L. A.
1996mpsa.conf..433C    Altcode: 1996IAUCo.153..433C
  No abstract at ADS

---------------------------------------------------------
Title: A Search for Asymmetric Flows in Young Active Regions
Authors: Cauzzi, G.; Canfield, R. C.; Fisher, G. H.
1996ApJ...456..850C    Altcode:
  We have studied the temporal evolution of photospheric velocities
  in young active regions that show evidence of ongoing magnetic
  flux emergence. We searched for asymmetries in the vertical plasma
  flows between the leading and following legs of the magnetic flux
  tubes. Such asymmetries are predicted in models of flux tubes rising
  in the convection zone (see the recent work of Fan, Fisher, &amp;
  DeLuca). These models, which successfully describe several aspects of
  active region formation, predict plasma flows from the leading to the
  following leg of a magnetic flux loop, driven by the Coriolis force
  acting on the rising loop. These flows contribute to an excess of
  gas pressure in the following leg with respect to the leading one. <P
  />Our results show a predominance of downflow in the leading part of
  three young regions with respect to the following part, contrary to
  the model predictions. The observed asymmetries, obtained by averaging
  over the totality of the magnetic structures, range from 60 to 150 m
  s<SUP>-1</SUP>. Their real value, however, could be higher if the age
  and effective magnetic filling factor were taken into account. The flow
  asymmetry seems to disappear when the active regions enter a phase
  of magnetic stability. <P />We suggest two possible interpretations
  of these results in terms of the dynamics of emerging magnetic flux
  tubes as the most plausible ones. One possibility is that the rising
  flux tube experiences severe fragmentation during the last stages of
  emergence through the convection zone. After fragmentation, the greater
  effect of aerodynamic drag strongly reduces the rise speed of the
  smaller flux tubes and hence the Coriolis force that drives the flows
  from the leading to the following leg of the magnetic loop. Since the
  higher gas pressure present in the following leg is no longer balanced,
  it will then drive a flow in the opposite direction, i.e., from the
  following to the leading side. Estimates of these pressure-driven
  flow velocities are consistent with the observed values. A second
  possibility is that the asymmetric flows originate from a preexisting
  superrotational velocity within high-field strength toroidal flux
  rings near the base of the solar convection zone. As pointed out
  in the recent work of Moreno-Insertis, Schussler, &amp; Ferriz-Mas,
  such superrotational velocities are required to maintain toroidal flux
  rings in dynamical equilibrium.

---------------------------------------------------------
Title: Emerging Flux, Reconnection, and XBP
Authors: van Driel-Gesztelyi, L.; Schmieder, B.; Demoulin, P.;
   Mandrini, C.; Cauzzi, G.; Hofmann, A.; Nitta, N.; Kurokawa, H.; Mein,
   N.; Mein, P.
1996mpsa.conf..459V    Altcode: 1996IAUCo.153..459V
  No abstract at ADS

---------------------------------------------------------
Title: Emerging flux seen by Yohkoh.
Authors: van Driel-Gesztelyi, L.; Schmieder, B.; Mandrini, C.;
   Démoulin, P.; Cauzzi, G.; Hofmann, A.; Nitta, N.; Kurokawa, H.;
   Mein, N.; Mein, P.
1996joso.proc..124V    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Coordinated observations of solar activity
    phenomena. I. Multispectral study of an elementary flare.
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.;
   Schwartz, R. A.; Hagyard, M.
1995A&A...299..611C    Altcode:
  In this paper we present a multispectral analysis of a small flare
  which may be considered as a sequence of elementary bursts rather than a
  collective flare phenomenon. A series of 5 short-lived (duration =~1-7s)
  emission spikes are in fact observed in hard X-ray (HXR). The flare was
  also observed in soft X-ray (SXR), with 3s temporal resolution, and in
  the optical range with very high spatial (=~0.5") and temporal (2.7s)
  resolutions. Sequences of filter images, in H<SUB>alpha</SUB>_ +1.5A,
  He-D_3_ and Na-D_2_ wavelengths were acquired. The flare impulsive
  phase, indicated by the occurrence of the HXR spikes, is preceded by
  an enhancement in the chromospheric and in the coronal SXR emissions
  starting, respectively, 40 and 15s before the flare. This indicates
  that a density and/or a temperature increase in the flaring loop starts
  at chromospheric levels, and only after this phase are the 5 separate
  electron beams sequentially accelerated and stopped in an atmosphere
  that is already modified. Four of the 5 HXR spikes are temporally
  associated with chromospheric emission features over small areas of
  3" size, while the fifth spike does not have detectable associated
  signatures. Apparent contradictions between H<SUB>alpha</SUB>_ +
  1.5 A and He-D_3_ emissions can be explained assuming atmospheric
  inhomogeneities, already present within the flaring loop. The flare
  occurs within an area of positive magnetic polarity, which shows a
  moderate but constant weighted magnetic shear. No inclusions of the
  opposite polarity are found in the flaring region, and no changes
  in the distribution of any of the magnetic field parameters are
  detected before, during and after the flare occurrence. No detectable
  modifications are measured in the continuum and in all the wavelength
  points of the Na-D_2_ line profile apart from the line core; this means
  that flare-associated modifications of the flaring loop atmosphere do
  not penetrate below the temperature minimum region.

---------------------------------------------------------
Title: Dynamics of Small Flux Tubes
Authors: Reger, Bernard; Keil, Stephen L.; Smaldone, Luigi A.; Cauzzi,
   Gianna; Balasubramaniam, K. S.
1994ASPC...68..157R    Altcode: 1994sare.conf..157R
  No abstract at ADS

---------------------------------------------------------
Title: Observations of Active Region Dynamics: Preflare Flows and
    Field Observations
Authors: Keil, Stephen L.; Balasubramaniam, K. S.; Bernasconi, Pietro;
   Smaldone, Luigi A.; Cauzzi, Gianna
1994ASPC...68..265K    Altcode: 1994sare.conf..265K
  No abstract at ADS

---------------------------------------------------------
Title: High temporal and spatial resolution observations of a solar
    flare on June 7, 1991
Authors: Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone, L. A.
1993AdSpR..13i.311C    Altcode: 1993AdSpR..13..311C
  We present some preliminary results on a small flare observed at the
  NSO-Sacramento Peak with very good spatial resolution (.6”-.7”). The
  flare occurred on June, 7 1991 at ~ 13:43 UT in the NOAA region 6659
  and has been observed by the COMPTON BATSE experiment in the 25-50 KeV
  range. A very complex velocity pattern is found for chromospheric and
  metallic lines: a small region (5” wide) presents a strong blue-shifts
  in all these lines, lasting through the flare, while, only in the Ca
  II-K and H<SUB>δ</SUB> lines, we find a zone (again ~ 5” wide) of
  strong red asymmetries contemporary to the hard X-rays spikes. These
  observations show the importance of having high spatial and temporal
  resolution measurements in the study of flares.

---------------------------------------------------------
Title: On the calibration of line-of-sight magnetograms
Authors: Cauzzi, G.; Smaldone, L. A.; Balasubramaniam, K. S.; Keil,
   S. L.
1993SoPh..146..207C    Altcode:
  Inference of magnetic fields from very high spatial, spectral, and
  temporal resolution polarized images is critical in understanding the
  physical processes that form and evolve fine scale structures in the
  solar atmosphere. Studying high spectral resolution data also helps
  in understanding the limits of lower resolution spectral data. We
  compare three different methods for calibrating the line-of-sight
  component of the magnetic field. Each method is tested for varying
  degrees of spectral resolution on both synthetic line profiles computed
  for known magnetic fields and real data. The methods evaluated are:
  (a) the differences in the center of gravity of the right and left
  circular components for different spectral resolution, (b) conversion
  of circular polarization, at particular wavelengths, to magnetic
  fields using model-dependent numerical solutions to the equations of
  polarized radiative transfer, and (c) the derivative method using
  the weak field approximation. Each method is applied to very high
  spatial and spectral resolution circular polarization images of an
  active region, acquired in the FeI 5250 å Zeeman-sensitive spectral
  line. The images were obtained using the 20 må pass-band tunable
  filter at NSO/Sacramento Peak Observatory Vacuum Tower Telescope. We
  find that the center-of-gravity separation offers the best way of
  inferring the longitudinal magnetic field.

---------------------------------------------------------
Title: Observation of solar flares at high resolution.
Authors: Cauzzi, G.; Falciani, R.; Falchi, A.; Smaldone, L. A.
1992ESASP.344..141C    Altcode: 1992spai.rept..141C
  The authors present some preliminary results of the observation of
  a flare performed at the NSO-Sacramento Peak with very good spatial
  resolution. The flare occurred on June 7, 1991 at ≡13:43 UT in the
  NOAA region 6659, showing an unusual high activity. A small region,
  ≡3″wide, shows strong blue shifts (of the order of the sound
  speed) in some metallic lines formed in the high photosphere, during
  the flare impulsive phase. These observations show the importance of
  having measurements at higher spatial and temporal resolution for an
  effective improvement of the knowledge of the fundamental dynamic of
  active regions and flares.

---------------------------------------------------------
Title: Two-dimensional solar spectroscopy with a Narrow Passband
    Filter.
Authors: Cauzzi, G.
1992lest.rept...19C    Altcode:
  The performances of a Narrow Passband Filter recently installed at
  NSO-SP are reviewed, in the framework of two-dimensional spectroscopy. A
  panoramic of the data reduction procedures and elaboration, together
  with samples of the physical parameters one can study, is given.

---------------------------------------------------------
Title: Variation of the Vector Magnetic Field in an Eruptive Flare
Authors: Rust, D. M.; Cauzzi, G.
1992LNP...399...46R    Altcode: 1992esf..coll...46R; 1992IAUCo.133...46R
  Observations of a 3B, M6 flare on April 2, 1991 appear to confirm
  earlier evidence that eruptive flares are triggered by measurable
  magnetic field changes. In the eight hours before the flare, the
  shear in the magnetic fields increased. The development that likely
  triggered the flare was the emergence into the active region and rapid
  proper motion of new flux. One of the small spots marking the negative
  magnetic leg of the new flux pushed into an established positive field
  at 0.2 km/s. Data from the JHU/APL vector magnetograph show that this
  motion led to the development of a sheared field. The flare started
  near the newly-sheared fields and spread to engulf most of the spot
  region. A magnetogram taken 45 min after flare onset shows possible
  relaxation of the sheared fields.

---------------------------------------------------------
Title: Narrow Bandpass Filter Solar Observations
Authors: Smaldone, L. A.; Cauzzi, G.; Keil, S. L.
1991BAAS...23.1057S    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: A New Method for Calibrating Vector Magnetograms
Authors: Cauzzi, G.; Rust, D. M.; O'Byrne, J. W.
1991BAAS...23R1054C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Two-Dimensional High-Resolution Spectroscopy of Quiet Regions
    on the Sun
Authors: Bonaccini, D.; Cauzzi, G.; Falchi, A.; Falciani, R.; Smaldone,
   L. A.
1990Ap&SS.170..117B    Altcode:
  We present preliminary results of solar bi-dimensional spectroscopy
  observations obtained with the new 20 mÅ NSO-Sacramento Peak tunable
  filter. The procedures of image destretching and the corrections for
  the modulation of the 5-min oscillations are briefly discussed.

---------------------------------------------------------
Title: Bi-dimensional solar spectroscopy with the 20 mÅ filter:
    capabilities and constraints.
Authors: Cauzzi, Gianna; Smaldone, Luigi A.
1990SPIE.1318..193C    Altcode:
  A new technique to perform bi-dimensional solar spectroscopy,
  by means of a narrow passband filter, is examined. The technique,
  combining high spatial and spectral resolution observations, allows
  the determination of the dynamic and thermodynamic parameters of the
  observed solar features, their spatial relationships and their evolution
  properties. The authors discuss this technique, its observational
  constraints and the data reduction procedures.

---------------------------------------------------------
Title: Some remarks on the data analysis problems in solar
    two-dimensional spectroscopy
Authors: Cauzzi, G.; Smaldone, L. A.; Bonaccini, D.; Falciani, R.
1989hsrs.conf..261C    Altcode:
  No abstract at ADS