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Author name code: strous
ADS astronomy entries on 2022-09-14
author:"Strous, Louis H."

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Title: The Formation of a Prominence in Active Region NOAA
    8668. I. SOHO/MDI Observations of Magnetic Field Evolution
Authors: Chae, Jongchul; Wang, Haimin; Qiu, Jiong; Goode, Philip R.;
   Strous, Louis; Yun, H. S.
2001ApJ...560..476C    Altcode:
  We have studied the evolution of the photospheric magnetic field in
  active region NOAA 8668 for 3 days while the formation of a reverse
  S-shaped filament proceeded. From a set of full-disk line-of-sight
  magnetograms taken by the Michelson Doppler Imager (MDI) on board
  the Solar and Heliospheric Observatory (SOHO), we have found a
  large canceling magnetic feature that was closely associated with
  the formation of the filament. The positive flux of the magnetic
  feature was initially 1.5×10<SUP>21</SUP> Mx and exponentially
  decreased with an e-folding time of 28 hr throughout the period of
  observations. We also have determined the transverse velocities of
  the magnetic flux concentrations in the active region by applying
  local correlation tracking. As a result, a persistent pattern of shear
  motion was identified in the neighborhood of the filament. The shear
  motion had a speed of 0.2-0.5 km s<SUP>-1</SUP> and fed negative
  magnetic helicity of -3×10<SUP>42</SUP> Mx<SUP>2</SUP> into the
  coronal volume during an observing run of 50 hr at an average rate
  of -6×10<SUP>40</SUP> Mx<SUP>2</SUP> hr<SUP>-1</SUP>. This rate is
  an order of magnitude higher than the rate of helicity change due to
  the solar differential rotation. The magnetic flux of the field lines
  created by magnetic reconnection and the magnetic helicity generated
  by the photospheric shear motion are much more than enough for the
  formation of the filament. Based on this result, we conjecture that the
  filament formation may be the visible manifestation of the creation
  of a much bigger magnetic structure that may consist of a flux rope
  and an overlying sheared arcade.

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Title: Bias in velocity determinations from full-disk solar
    observations
Authors: Strous, L. H.
2000SoPh..195..219S    Altcode:
  Estimates for the global solar surface velocity field can be
  obtained from time series of full-disk solar images. However, bias
  is introduced by mistakes in the assumptions about the geometry of
  the observations, and by imperfections in the optical system. I
  investigate many sources of bias and determine their first-order
  influence on the measured velocity field (both the transverse and
  longitudinal components). Results are presented in analytical and
  pictorial form. By comparing bias velocities of unknown origin with
  the results, one may obtain clues to the cause of the bias.

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Title: The Dynamics of the Excitation of Solar Oscillations
Authors: Strous, Louis H.; Goode, Philip R.; Rimmele, Thomas R.
2000ApJ...535.1000S    Altcode:
  We investigate seismic events, bursts of seismic waves that are
  generated locally just below the solar surface and that we detect
  traveling up through the photosphere. We identify a few thousand
  seismic events by their traveling wave character and find that they
  are associated with continuum darkening and downflow and have an
  extent of on average about 10-15 minutes and 1 Mm. Their birth rate
  is about 8×10<SUP>-16</SUP> m<SUP>-2</SUP> s<SUP> -1</SUP>. The
  observed upwardly traveling seismic flux in the average event
  (as derived from velocities in the p-mode region of k-ω space) is
  followed after about 3 minutes by some reflected downward flux. Only
  a small fraction of the energy generated in the hypocenter of the
  event below the surface travels straight up for us to see. The bulk
  of the generated energy is directed or reflected downward, and is
  eventually transformed into p-modes. The seismic events at the surface
  contain about 1.5×10<SUP>19</SUP> J of seismic energy each, which
  corresponds to an average flux level of about 8.5 kW m<SUP>-2</SUP>
  over the whole surface. The total energy flow is likely more than an
  order of magnitude greater, and is then in the same ballpark as the
  estimate of Libbrecht for the power required to sustain the p-mode
  spectrum. We find a roughly linear relation between the peak seismic
  flux and the peak downward convective velocity associated with each
  seismic event, which does not fit the highly nonlinear relations found
  theoretically by Lighthill and Goldreich &amp; Kumar for stochastic
  excitation by turbulent convection, but does fit the monopole source
  deduced by Nigam &amp; Kosovichev from a study of the p-mode spectrum.

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Title: Large-Scale Surface Flow Patterns on the Sun
Authors: Strous, L. H.
2000SPD....31.0104S    Altcode: 2000BAAS...32..801S
  I derive the large-scale flow field at the solar surface from tracking
  features at supergranular scale (10 Mm) through SOHO/MDI full-disk
  Dopplergrams recorded during 62 days in 1996 and reduced at Stanford
  University to a dataset with a pixel scale of 1.39 Mm and a cadence of
  15 minutes. Both the dataset and the reduction algorithms are improved
  compared to earlier investigations. I present measurements, derived from
  supergranular motion, of differential rotation and meridional flow, and
  synoptic maps of the solar surface flow and its variation in time. This
  work is supported by the SOI/MDI project at Stanford University and
  Lockheed Martin Solar &amp; Astrophysics Laboratory (grant NAG5-3077).

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Title: De veranderlijke zon.
Authors: Strous, L.
2000Zenit..27..148S    Altcode:
  No abstract at ADS

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Title: Phenomena in an Emerging Active Region. II. Properties of
    the Dynamic Small-Scale Structure
Authors: Strous, Louis H.; Zwaan, Cornelis
1999ApJ...527..435S    Altcode:
  The magnetic flux emergence in growing active region NOAA 5617,
  when it is about 8 hr old, shows an intricate fine structure. The
  small-scale emergence events are characterized by a coincident
  upflow and transient darkening (of about 2 Mm and 10 minutes) in the
  continuum and line-center intensity followed by the appearance of one,
  or in some cases two, new bright grains flanking the line-center
  darkening. The bright grains (faculae) coincide with magnetic
  flux concentrations and downflows. The footpoints move apart at on
  average 1.4 km s<SUP>-1</SUP>. Flux emergence happens recurrently in
  a number of locations widely distributed over the active region, which
  appear to form a pattern with a wavelength of about 8 Mm. A preferred
  orientation that fits Hale's polarity law is displayed by the spatial
  pattern in the emergence locations, the emergence events themselves,
  subsequent footpoint motion, and the Hα arch filament system. We find
  long (~15 Mm) alignments of unipolar faculae of each magnetic polarity
  that also follow the preferred orientation. We adapt the model for flux
  emergence to accommodate the observed dynamic fine structure. Essential
  new features are (1) the emerging bundle of flux tubes is frayed in
  two systems, in vertical stacks, arranged in slightly curved, nearly
  parallel sheets; and (2) many flux tubes emerge in multiple locations.

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Title: Solar Differential Rotation Derived from H-alpha Full Disk
    Images by Means of Local Correlation Tracking
Authors: Woodard, M. F.; Denker, C.; Strous, L. H.; BBSO Collaboration;
   LMSAL Collaboration
1999AAS...19410007W    Altcode: 1999BAAS...31..997W
  We present the application of Local Correlation Tracking (LCT)
  techniques to time series of contrast-enhanced H-alpha full disk images
  taken as part of the synoptic observing program at Big Bear Solar
  Observatory (BBS0) during the summer of 1998. A typical set of daily
  H-alpha full disk images consists of 600 to 800 individual frames,
  taken 30 to 60 s apart, with a 2k x 2k pixel Kodak 4.2 MegaPlus CCD
  camera at BBSO's Singer telescope. For each pair of successive images,
  we compute displacement vectors over a 64 x 64 element cartesian
  grid covering the solar disk. The resulting daily-averaged flow maps
  show predominantly solar differential rotation and proper motions in
  active regions. We remap the flow maps to heliographic coordinates and
  determine a Legendre polynomial expansion of the daily differential
  rotation profile. We present preliminary findings regarding differential
  rotation based on different types of features seen in H-alpha, such as
  quiet-sun fibrils, plages, and dark filaments. We discuss the relation
  of our differential rotation profiles to profiles derived by other
  methods and address the question of time variability. The work at
  BBSO is supported by ONR under grant N00014-97-1-1037, by NSF under
  grant ATM 97-14796, and by NASA under grant NAG 5-4919. Louis Strous
  is supported by NASA NAG5-3077 to Stanford University.

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Title: Average Properties of Flux Emergence in Young Active Region
    5617
Authors: Strous, L.
1999ASPC..183..551S    Altcode: 1999hrsp.conf..551S
  No abstract at ADS

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Title: Properties of Small-Scale Flux Emergence in a Young Active
    Region
Authors: Strous, Louis; Zwaan, Cornelis
1999soho....9E..82S    Altcode:
  The magnetic flux emergence in growing active region NOAA 5617, when
  it is about 8 hours old, shows an intricate fine structure. The
  small-scale emergence events are characterized by a coincident
  upflow and transient darkening (of about 2 Mm and 10 minutes) in the
  continuum and line-center intensity, followed by the appearance of
  one, or in some cases two, new bright grains flanking the line-center
  darkening. The bright grains (faculae) coincide with magnetic flux
  concentrations and downflows. The footpoints move apart at on average
  1.4 km/s. Flux emergence happens recurrently in a number of locations
  widely distributed over the active region, which appear to form
  a pattern with a wavelength of about 8 Mm. A preferred orientation
  which fits Hale's polarity law is displayed by the spatial pattern in
  the emergence locations, the emergence events themselves, subsequent
  footpoint motion, and the H-alpha arch filament system. We find long
  (~ 15 Mm) alignments of unipolar faculae of each magnetic polarity
  that also follow the preferred orientation. We adapt the model for flux
  emergence to accommodate the observed dynamic fine structure. Essential
  new features are: (1) the emerging bundle of flux tubes is frayed in
  two systems; in vertical stacks, arranged in slightly curved, nearly
  parallel sheets, and (2) many flux tubes emerge in multiple locations.

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Title: The Excitation of Solar Oscillations -- Observations and
    Simulations
Authors: Goode, P.; Strous, L.; Rimmele, T.; Stein, R.; Nordlund, Å.
1999ASPC..183..456G    Altcode: 1999hrsp.conf..456G
  No abstract at ADS

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Title: The Excitation of Solar Oscillations
Authors: Strous, Louis H.; Goode, Philip R.; Rimmele, Thomas R.
1999soho....9E..81S    Altcode:
  We investigate seismic events, bursts of seismic waves that are
  generated locally just below the solar surface and that we detect
  travelling up through the photosphere. We identify 646 seismic events,
  which are associated with intergranular lanes and have an extent
  of on average about 10 minutes and 3 Mm. Their birth rate is about
  10-16 m-2 s-1. The observed upwardly travelling seismic flux in the
  average event (as derived from velocities in the p-mode region of
  k-omega space) is followed after about 5 minutes by some reflected
  downward flux. Only some of the energy generated in the hypocenter of
  the event below the surface travels up for us to see. We propose that
  this energy is converted into surface (f-mode-like) waves, while the
  unseen, initially downward going energy is eventually transformed
  into p-modes. The seismic events at the surface contain about 5 *
  1019 J of seismic energy each, which corresponds to an average
  flux level of about 4 kW/m2 over the whole surface. The initially
  downward directed energy flow is likely substantially greater, and
  is then in the same ballpark as the estimate of Libbrecht (1988) for
  the power required to sustain the p-mode spectrum. We find a roughly
  linear relation between the peak seismic flux and the peak downward
  convective velocity associated with each seismic event, which is
  not equal to the v8 relation found theoretically by Lighthill (1952)
  for stochastic excitation by turbulent convection.

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Title: On the Origin of Solar Oscillations
Authors: Goode, Philip R.; Strous, Louis H.; Rimmele, Thomas R.;
   Stebbins, Robin T.
1998ApJ...495L..27G    Altcode: 1998astro.ph..1008G
  We have made high-resolution observations of the Sun in which we
  identify individual sunquakes and see power from these seismic events
  being pumped into the resonant modes of vibration of the Sun. A typical
  event lasts about 5 minutes. We report the physical properties of
  the events and relate them to theories of the excitation of solar
  oscillations. We also discuss the local seismic potential of these
  events.

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Title: 62 Days Around the Sun: A Search for Supergranular Evolution
    and Giant Cells
Authors: Strous, Louis H.; Simon, George W.
1998ASPC..140..161S    Altcode: 1998ssp..conf..161S
  No abstract at ADS

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Title: Supergranular Evolution, Solar Rotation, and a Search for
    Giant Cells, using Full-disk SOHO/SOI/MDI Dopplergrams
Authors: Simon, George W.; Strous, Louis H.
1997AAS...19112002S    Altcode: 1997BAAS...29.1402S
  SOHO/SOI/MDI obtained full-disk dopplergrams of the Sun once per minute
  for 62 days from 1996 May 23 to 1996 July 23. From hourly averages
  of these dopplergrams we have studied the evolution of supergranules,
  measured solar rotation up to high latitudes, and searched for giant
  cells.

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Title: Photospheric Differential Rotation from Full-Disk SOI/MDI
    Dopplergrams
Authors: Bogart, R. S.; Bai, T.; Scherrer, P. H.; Strous, L. H.;
   Simon, G. W.; Tarbell, T. D.
1997SPD....28.0258B    Altcode: 1997BAAS...29..903B
  We report on measurements of the solar surface differential rotation
  made from SOI/MDI full-disk Dopplergrams obtained once per minute during
  the 2-month Dynamics Program from 23 May through 26 July 1996. We infer
  the rotation profile both from the direct photospheric Doppler signal
  and also by tracking Doppler features (supergranules) across the solar
  disk. We study the rotation curve as a function of latitude, feature
  size, and tracking method, and look for global scale flows. This work
  was supported by NASA Grant NAG5-3077 at Stanford and Lockheed Martin,
  and by AFOSR and the Fellows Program of AF Phillips Lab at NSO/SP.

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Title: Comparison of Granulation Correlation Tracking (CT) and
    Feature Tracking (FT) Results from SOHO/MDI and the Swedish Vacuum
    Solar Telescope on La Palma
Authors: Shine, R.; Strous, L.; Simon, G.; Berger, T.; Hurlburt, N.;
   Tarbell, T.; Title, A.; Scharmer, G.
1997SPD....28.0262S    Altcode: 1997BAAS...29Q.904S
  We have computed photospheric velocity flow maps from simultaneous
  observations taken with MDI and at the Swedish Vacuum Solar Tower
  (SVST) on La Palma on August 15, 1996. Both sets consist of a series
  of photospheric images, and flow maps are computed by following the
  local motions of granules. The MDI data have the important advantages
  of very stable images and longer continuous coverage of the same area
  of the solar surface. This longer coverage is necessary to study the
  evolution of mesogranules, supergranules, and to detect possible low
  amplitude motions on scales larger than supergranules. However, the
  high resolution mode of MDI is limited by the small telescope size to
  about 1.2 arc seconds angular resolution and uses a 0.6 arc second pixel
  size. This is adequate to show granulation but has the rms constrast
  significantly reduced to about 2%. Early efforts adapting techniques
  that were successful with higher resolution ground based images gave
  poor results and although new methods have now been developed, there
  are still some problems with accuracy. On the other hand, the SVST
  images have much higher angular resolution (as good as 0.2 arc second)
  but suffer from variable atmospheric distortion. They also have a much
  smaller field of view. By detailed comparison of the two data sets
  and by using CT and FT techniques to track the motions, we hope to
  understand the sources of any differences between them and to develop
  credible correction parameters to the MDI data sets if necessary. This
  work was supported by NASA Grant NAG5-3077 at Stanford and Lockheed
  Martin, by AFOSR and the Fellows Program of AF Phillips Lab at NSO/SP,
  and by the Swedish Royal Academy of Sciences.

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Title: Preliminary SoHO/MDI Observations of Supergranular Evolution
Authors: Simon, G. W.; Strous, L. H.; Matt, S.; Title, A. M.;
   Schrijver, C. J.
1997SPD....28.0264S    Altcode: 1997BAAS...29R.904S
  We present preliminary results of a study into the evolution of
  supergranules, using data from SoHO/MDI. We discuss the supergranular
  size spectrum, lifetimes, and topological evolution. We compare
  structures of supergranular size visible in high-resolution SoHO/MDI
  dopplergrams and in divergence maps derived from tracking of features
  in dopplergrams. This work was supported by NASA Grant NAG5-3077 at
  Stanford and Lockheed Martin, and by AFOSR and the Fellows Program of
  AF Phillips Lab at NSO/SP.

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Title: Horizontal Velocity Structure of Supergranules near Disk
    Center from High-Resolution SoHO/MDI Observations
Authors: Strous, L. H.; Simon, G. W.; Shine, R. A.; Hurlburt, N.
1997SPD....28.0265S    Altcode: 1997BAAS...29S.904S
  We determine the average surface flows in supergranules from
  high-resolution SoHO/MDI observations near disk center, using local
  correlation and feature tracking methods. We present results as a
  function of distance to the supergranule center and of supergranule
  size, and as a function of normalized distance to the supergranule
  center. This work was supported by NASA Grant NAG5-3077 at Stanford and
  Lockheed Martin, and by AFOSR and the Fellows Program of AF Phillips
  Lab at NSO/SP.

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Title: Comparison of supergranular flows from doppler and local
    correlation tracking velocities
Authors: Frank, Z.; Hurlburt, N.; Shine, R.; Tarbell, T.; Simon, G.;
   Strous, L.; Matt, S.
1997SPD....28.0259F    Altcode: 1997BAAS...29..903F
  Measurements of the flows in the solar photosphere rely upon two
  techniques: doppler measurements of the line-of-sight velocity
  or tracking of features or patterns moving perpendicular to the
  line-of-sight. These methods have differing characteristics. Doppler
  measurements can easily measure surface flows near the limb
  which are not seriously contaminated by p-modes or other solar
  sources. However, they require excellent instrument calibration over
  the full field of view. Even then vertical flows within supergranules
  are barely detectable. Correlation and feature tracking have proven
  useful for estimating transverse velocity using granules and other
  tracers. Nevertheless, they can be degraded by the intensity variations
  of p-modes and possibly other oscillatory motions, as well as by effects
  of limb darkening and foreshortening. The two methods would both be
  strengthened through detailed comparisons. Data collected by MDI/SOHO is
  ideal for this purpose. The data is co-spatial and co-temporal, and is
  all obtained through the same instrument. We compare Doppler velocities
  with those obtained through correlation tracking using high-resolution
  MDI/SOHO images. We focus on motions at positions exceeding 30 degrees
  from disk center. After taking projection effects into account, we
  combine the two measurements to form a three-dimensional picture of
  the flows in the average supergranule. This work was supported by NASA
  Grant NAG5-3077 at Stanford and Lockheed Martin, and by AFOSR and the
  Fellows Program of AF Phillips Lab at NSO/SP.

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Title: Dynamics of the Chromospheric Network: Mobility, Dispersal,
    and Diffusion Coefficients
Authors: Schrijver, Carolus J.; Shine, Richard A.; Hagenaar, Hermance
   J.; Hurlburt, Neal E.; Title, Alan M.; Strous, Louis H.; Jefferies,
   Stuart M.; Jones, Andrew R.; Harvey, John W.; Duvall, Thomas L., Jr.
1996ApJ...468..921S    Altcode:
  Understanding the physics behind the dispersal of photo spheric magnetic
  flux is crucial to studies of magnetoconvection, dynamos, and stellar
  atmospheric activity. The rate of flux dispersal is often quantified by
  a diffusion coefficient, D. Published values of D differ by more than a
  factor of 2, which is more than the uncertainties allow. We propose that
  the discrepancies between the published values for D are the result of
  a correlation between the mobility and flux content of concentrations of
  magnetic flux. This conclusion is based on measurements of displacement
  velocities of Ca II K mottles using an uninterrupted 2 day sequence
  of filtergrams obtained at the South Pole near cycle minimum. We
  transform the Ca II K intensity to an equivalent magnetic flux density
  through a power-law relationship defined by a comparison with a nearly
  simultaneously observed magnetogram. One result is that, wherever the
  network is clearly defined in the filtergrams, the displacement vectors
  of the mottles are preferentially aligned with the network, suggesting
  that network-aligned motions are more important to field dispersal than
  deformation of the network pattern by cell evolution. The rms value
  of the inferred velocities, R = &lt;|v|<SUP>2</SUP>&gt;<SUP>½</SUP>,
  decreases with increasing flux, Φ, contained in the mottles, from R
  ≍ 240 m s<SUP>-1</SUP> down to 140 s<SUP>-1</SUP>. The value of R(Φ)
  appears to be independent of the flux surrounding the concentration,
  to the extreme that it does not matter whether the concentration is
  in a plage or in the network. The determination of a proper effective
  diffusion coefficient requires that the function R(Φ) be weighted
  by the number density n(Φ) of mottles that contain a total flux. We
  find that n(Φ) decreases exponentially with Φ and propose a model
  of continual random splitting and merging of concentrations of flux to
  explain this dependence. Traditional methods used to measure D tend to
  be biased toward the larger, more sluggish flux concentrations. Such
  methods neglect or underestimate the significant effects of the
  relatively large number of the more mobile, smaller concentrations. We
  argue that the effective diffusion coefficient for the dispersal of
  photo spheric magnetic flux is ∼600 km<SUP>2</SUP> s<SUP>-1</SUP>.

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Title: Observation of the excitation of solar oscillations
Authors: Goode, Philip R.; Strous, Louis H.
1996BASI...24..223G    Altcode:
  No abstract at ADS

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Title: Preliminary SOI/MDI Observations of Surface Flows by
    Correlation Tracking in the Quiet Solar Photosphere and an Emerging
    Active Region
Authors: Tarbell, T.; Frank, Z.; Hurlburt, N.; Saba, J.; Schrijver,
   C.; Shine, R.; Title, A.; Simon, G.; Strous, L.
1996AAS...188.6914T    Altcode: 1996BAAS...28..937T
  The extended observation of the solar surface with frequent sampling
  provided by MDI on SoHO offers the chance to observe the evolution of
  supergranules and to measure surface flows associated with active
  regions and perhaps larger scale zonal and meridonal flows. We
  have used local correlation tracking of the granulation pattern for
  measuring surface flows from MDI high resolution continuum images. The
  datasets consist of 1024 x 1024 pixel images collected with a cadence
  of one minute and extending many hours each. The images are typically
  centered upon the central meridian of the sun and offset to the north
  of sun center, spanning roughly 40 degrees of solar longitude and from
  approximately -10 to +30 degrees of solar latitude. The latitude
  dependence of the differential rotation is evident. We present
  preliminary results of our search for signatures of mesogranules,
  supergranules and giant cells. On 23 Feb. 1996, we obtained a 12-hour
  continuous sequence including quiet sun near disk center and NOAA
  region 7946 at about N08 E30. The active region grew rapidly over this
  interval, forming several sunpots. We show preliminary comparisons of
  the measured flow fields with coaligned SOI/MDI magnetograms taken
  at 15-minute intervals. The SOI/MDI program is supported by NASA
  grant NAG5-3077.

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Title: Phenomena in an emerging active region. I. Horizontal dynamics.
Authors: Strous, L. H.; Scharmer, G.; Tarbell, T. D.; Title, A. M.;
   Zwaan, C.
1996A&A...306..947S    Altcode:
  Horizontal dynamics in observations of NOAA AR 5617 are studied by
  tracking individual elements through the field of view. Small magnetic
  elements of both magnetic polarities occur everywhere in the active
  region, and define unipolar thread-like concentrations of magnetic
  field of up to 15Mm length. The horizontal granular flow field in
  the active region is divergent (e-time scale 2.1hours) and clockwise
  (time scale 32hours). Facular elements are tracers of (clumps of)
  fluxtubes. A hierarchy of movement of magnetic elements appears:
  Facular elements everywhere in the active region move obliquely toward
  the edges of the active region of the same polarity as their own, faster
  than those edges (as defined by strings of pores) move apart. The pores
  move along the edges toward the major sunspots of their own polarity,
  and the major sunspots of either polarity move apart. The separation
  velocity of both polarities of facular elements is about 0.84km/s, of
  pores about 0.73km/s, and that of the major sunspots is about 0.50km/s.

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Title: Dark Lanes in Granulation and the Excitation of Solar
    Oscillations
Authors: Rimmele, T. R.; Goode, P. R.; Strous, L. H.; Stebbins, R. T.
1995ESASP.376b.329R    Altcode: 1995help.confP.329R; 1995soho....2..329R
  No abstract at ADS

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Title: Warning: Local Correlation Tracking may BE Dangerous to your
    (scientific) Health
Authors: Simon, G. W.; Brandt, P. N.; November, L. J.; Shine, R. A.;
   Strous, L. H.
1995ESASP.376b.223S    Altcode: 1995soho....2..223S; 1995help.confP.223S
  No abstract at ADS

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Title: Feature Tracking: Deriving Horizontal Motion and More
Authors: Strous, L. H.
1995ESASP.376b.213S    Altcode: 1995help.confP.213S; 1995soho....2..213S
  No abstract at ADS

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Title: Comparison of Flow Maps Derived by Various Techniques
Authors: Strous, L. H.
1995ESASP.376b.219S    Altcode: 1995help.confP.219S; 1995soho....2..219S
  No abstract at ADS

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Title: Dynamics in Solar Active Regions: Patterns in Magnetic-Flux
    Emergence
Authors: Strous, L. H.
1994PhDT.......347S    Altcode:
  No abstract at ADS

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Title: Dynamics of small magnetic elements in a growing active region
Authors: Strous, L. H.
1994ASIC..433...73S    Altcode:
  No abstract at ADS

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Title: Predictions of infrared recombination lines in stellar winds
    of hot stars
Authors: Strous, L. H.; Lamers, H. J. G. L. M.
1989ESASP.290..385S    Altcode: 1989isa..book..385S
  Infrared recombination lines can provide accurate estimates
  for the velocity and density structure of stellar winds and
  thus of mass loss. The authors use a simple stellar wind model,
  hydrogenic approximations and scaling laws to derive information about
  recombination lines in the ISO range (1 - 100 μm). They estimate that,
  for a 40000K star, the boundary-level from above which recombination
  lines originate is in the range n = 2 - 10 for the most abundant
  elements. The authors give a simple formula to estimate the population
  of levels above the boundary-level and use this to produce a table
  of predictions of fluxes and equivalent widths of recombination lines
  for H, He, C III-IV, N III-V and O III-V.