Author name code: hagino ADS astronomy entries on 2022-09-14 author:"Hagino, Masaoki" ------------------------------------------------------------------------ Title: 2021 HC3 Authors: Denneau, L.; Tonry, J.; Heinze, A.; Weiland, H.; Fitzsimmons, A.; Robinson, J.; Erasmus, N.; Pruyne, T. A.; Christensen, E. J.; Farneth, G. A.; Fuls, D. C.; Gibbs, A. R.; Grauer, A. D.; Groeller, H.; Kowalski, R. A.; Larson, S. M.; Leonard, G. J.; Rankin, D.; Seaman, R. L.; Shelly, F. C.; Wierzchos, K. W.; Dupouy, P.; Hidas, A.; Holmes, R.; Foglia, S.; Buzzi, L.; Linder, T.; Hug, G.; Romanov, F. D.; Losse, F.; D'Anna, W.; Birtwhistle, P.; Okumura, S.; Hagino, M.; Flynn, R. L.; Jacques, C.; Pimentel, E.; Barros, J.; Wells, G.; Leuty, J. Bibcode: 2021MPEC....J...16D Altcode: No abstract at ADS Title: Development of new tunable filter for solar observation in Hida observatory Authors: Otsuji, Kenichi; Kimura, Gouichi; Nakatani, Yoshi-kazu; Kaneda, Naoki; Ishii, Takako T.; Hagino, Masaoki; Ichimoto, Kiyoshi Bibcode: 2020SPIE11447E..A5O Altcode: Solar Magnetic Activity Research Telescope (SMART) at Hida observatory is in operational to monitor the solar activity. As a new solar Hα observing instrument for SMART, we developed "Solar Dynamics Doppler Imager (SDDI)", which can measure the three-dimensional motion of solar eruptive phenomena. These eruptive events could be affective to the earth magnetism and cause serious damage to our society. The purpose of SMART/SDDI is monitoring and forecasting the geo-affective solar eruptions. In this paper, we present the development of the tunable filter "F40", the key component of SDDI. The features of TF40 are, (1) fast tuning of observation wavelength, (2) narrow transmission width and large free spectral range (FSR), (3) large field-of-view that covers the entire solar disk with a 20 cm objective lens. TF40 has 7 stages of optical blocks. Each stage consists of a linear polarizer, calcites, a quartz as half waveplate and a Liquid Crystal Variable Retarder (LCVR), and has the periodic transmission profile with 0.05, 0.1, 0.2, 0.4, 0.8, 1.6 and 3.2 nm period at Hα line (656.2808 nm), respectively. Combining the 7 stages, the 0.025 nm transmission width and 3.2 nm FSR are achieved. Retardation of each LCVR and its dependence on applied voltage and temperature were measured for modeling its characteristics, with which we calculate the voltage for desired retardation. Best-shaped transmission profile is obtained by further adjustment of voltages of individual LCVRs using the real solar light. We report the performance and current observing status of the TF40. Title: Infrared spectro-polarimeter on the Solar Flare Telescope at NAOJ/Mitaka Authors: Sakurai, Takashi; Hanaoka, Yoichiro; Arai, Takehiko; Hagino, Masaoki; Kawate, Tomoko; Kitagawa, Naomasa; Kobiki, Toshihiko; Miyashita, Masakuni; Morita, Satoshi; Otsuji, Ken'ichi; Shinoda, Kazuya; Suzuki, Isao; Yaji, Kentaro; Yamasaki, Takayuki; Fukuda, Takeo; Noguchi, Motokazu; Takeyama, Norihide; Kanai, Yoshikazu; Yamamuro, Tomoyasu Bibcode: 2018PASJ...70...58S Altcode: 2018PASJ..tmp...63S; 2018PASJ..tmp...82S An infrared spectro-polarimeter installed on the Solar Flare Telescope at the Mitaka headquarters of the National Astronomical Observatory of Japan is described. The new spectro-polarimeter observes the full Sun via slit scans performed at two wavelength bands, one near 1565 nm for a Zeeman-sensitive spectral line of Fe I and the other near 1083 nm for He I and Si I lines. The full Stokes profiles are recorded; the Fe I and Si I lines give information on photospheric vector magnetic fields, and the helium line is suitable for deriving chromospheric magnetic fields. The infrared detector we are using is an InGaAs camera with 640 × 512 pixels and a read-out speed of 90 frames s-1. The solar disk is covered by two swaths (the northern and southern hemispheres) of 640 pixels each. The final magnetic maps are made of 1200 × 1200 pixels with a pixel size of 1{^''.}8. We have been carrying out regular observations since 2010 April, and have provided full-disk, full-Stokes maps, at the rate of a few maps per day, on the internet. Title: Image enhancement for the observation of the solar corona Authors: Zhao, M. Y.; Liu, Y.; Song, T. F.; Zhang, X. F.; Hagino, M.; Sakurai, T. Bibcode: 2018SPIE10701E..29Z Altcode: In this work, we introduce an image enhancement method ideally suited for the visualization of coronal intensity images. The steep radial gradient of the coronal brightness is adjusted by normalising the coronal image with the Fourier approximation of its local average. A method based on deconvolution and localised normalising of the data at many different spatial scales is used to further enhance the fine structures, and a wavelet shrinkage denoising method is used for noise suppression. The effectiveness of this method is demonstrated on a series of images observed by various instruments including spacial and earth-based coronagraphs as well as photos during total solar eclipse. This method is very helpful for qualitative analysis of solar coronal structures that are mostly invisible on original images. Title: Development of the Universal Tunable Filter and High-resolution Imaging Observation with the Fuxian Solar Observatory Authors: Hagino, M.; Ichimoto, K.; Ueno, S.; Kimura, G.; Otsuji, K.; Kitai, R.; Zhong, L.; Xu, Z.; Shinoda, K.; Hara, H.; Suematsu, Y.; Shimizu, T. Bibcode: 2016ASPC..504..103H Altcode: We have developed a new narrow-band universal tunable filter to perform imaging spectroscopy of the solar chromosphere. The development stage of the filter has been almost finished and we shifted to the scientific observation phase by using large grand-based telescopes. Using the filter, a series of high-resolution images were obtained with the 1m vacuum solar telescope at the Fuxian Solar Observatory. We succeeded in observing several flares and fine structures of the chromospheric layer. Title: Development of a universal tunable filter for future solar observations Authors: Hagino, M.; Ichimoto, K.; Kimura, G.; Nakatani, Y.; Kawate, T.; Shinoda, K.; Suematsu, Y.; Hara, H.; Shimizu, T. Bibcode: 2014SPIE.9151E..5VH Altcode: We have developed a new narrowband tunable filter to perform imaging spectroscopy of the solar chromosphere. Using Liquid Crystal Variable Retarders (LCVRs) as the tuning elements for wavelength, wide-band polarizers and super achromatic half-wave plates, it is possible to make high speed tuning (about 0.1Sec), to exclude mechanical drives (and oil tank), and to cover a wide wavelength range (510-100nm). This filter builds up with seven stages each consisting of a pair of calcites, LCVR, half-wave plates and linear polarizer. The full width at half maximum (FWHM) of the filter transmission is about 0.025nm at 656.3nm.We demonstrate that the concept of the universal tunable filter using the LCVR's as tuning elements is highly promising for future application to space mission and ground based observations. Title: Magnetic Helicity of Solar Active Regions as Revealed by Vector Magnetograms and Coronal X-Ray Images Authors: Xu, Haiqing; Gao, Yu; Zhang, Hongqi; Sakurai, Takashi; Hagino, Masaoki; Sokoloff, Dmitry; Pevtsov, Alexei A. Bibcode: 2012PASJ...64...54X Altcode: We have used photospheric vector magnetograms of 15 different solar active regions to calculate the current helicity parameter, αav, and the linear force-free field (LFFF) parameter, αbest, that fits best the observed transverse field. The data were obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station, the National Astronomical Observatories of China, the Solar Flare Telescope of the National Astronomical Observatory of Japan, and the Haleakala Stokes Polarimeter at the Mees Solar Observatory, University of Hawaii, from 1997 to 2000. The agreement in sign of αav between three vector magnetographs is better than 90%. For αbest, the agreement is 80%-90%. The line-of-sight magnetograms observed with the Michelson-Doppler Imager (MDI) on SOHO and coronal X-ray images observed with the Soft X-ray Telescope (SXT) on Yohkoh have been used to determine the constant αc of the LFFF in the corona. The value of αc corresponds to the extrapolated coronal field whose field lines best match, by visual inspection, the structure of coronal loops in X-ray images. It is found that the sign agreement between photospheric αav or αbest and coronal αc is lower (60%-85%). We consider the differences in measurements, observing conditions, data reduction methods, and limitation in LFFF extrapolation, and discuss their contributions to the dispersions in the hemispheric sign rule of helicity. Title: Infrared Stokes Spectro-Polarimeter at the National Astronomical Observatory of Japan Authors: Hanaoka, Y.; Sakurai, T.; Shinoda, K.; Noguchi, M.; Miyashita, M.; Fukuda, T.; Suzuki, I.; Hagino, M.; Arai, T.; Yamasaki, T.; Takeyama, N. Bibcode: 2011ASPC..437..371H Altcode: We are now constructing an infrared spectro-polarimeter for the Solar Flare Telescope of NAOJ. It observes the full Sun in two wavelength bands, one near 1.56 μm for highly Zeeman-sensitive spectral lines of Fe I and the other near 10830 Å for He I and Si I lines. The instrument records full Stokes profiles, and a Stokes inversion process will give information on the strength and orientation of the magnetic field vector for both of the photosphere and the chromosphere. The infrared detector we are using is an InGaAs camera manufactured by a Belgian company Xenics. Its format is 640×512 pixels and its read-out speed is 90 frames s-1. The solar disk will be covered by two swaths (the northern and southern hemispheres) of 640 pixels each. The final magnetic maps will be made of 1200×1200 pixels with a pixel size of 1.8 arcsec. Now we are operating regular observations and generate full-disk, full-Stokes maps (a few maps per day). Our ultimate goal is to derive the distribution of magnetic helicity over the whole surface of the Sun, not only in sunspots and active regions. Title: Quantitative Comparison between the Polarization Data Taken with the Solar Flare Telescope and with the Hinode SOT Spectro-Polarimeter Authors: Hagino, M.; Hanaoka, Y.; Sakurai, T.; Ichimoto, K. Bibcode: 2011ASPC..437..359H Altcode: The aim of this study is to establish the method to derive correct vector magnetic fields from imaging polarimetry data taken with the Solar Flare Telescope of the National Astronomical Observatory of Japan. We compared our imaging polarimetry data taken during 2006 December with the spectro-polarimetry data taken with the Hinode Solar Optical Telescope. While the polarization signals obtained with the two instruments are basically consistent to each other, we found some systematic differences between them, particularly in transverse magnetic field vectors. Title: Developments of the Multi-wavelength Polarimeter of the Domeless Solar Telescope at the Hida Observatory Authors: Anan, T.; Ichimoto, K.; Ueno, S.; Kimura, G.; Nakatani, Y.; Kaneda, N.; Hagino, M.; Suzuki, I. Bibcode: 2011ASPC..437..365A Altcode: A new universal spectropolarimeter is developed on the Domeless Solar Telescope (DST) at the Hida Observatory to realize precise spectropolarimetric observations in a wide range of wavelengths in visible and near infrared. The system aims to open a new window of plasma diagnostics by using Zeeman effect, Hanle effect, Stark effect and impact polarization for measuring the chromospheric magnetic fields, electric fields and unisotropically accelerated particles in the solar atmosphere.

The new system consists of a 60 cm aperture vacuum telescope, a high dispersion vacuum spectrograph, polarization modulator/analyser composed of a rotating waveplate and a Wallaston prism located after the entrance slit of the spectrograph, and a fast and large format CCD camera.

Spectral images in both orthogonal polarizations are taken simultaneously with a frame rate of ∼20 Hz while the waveplate rotates continuously in a rate of 1 rev./sec. Thus a high signal to noise ratio can be achieved in a short time. To calibrate the instrumental polarization of the telescope a remotely controllable turret accommodating linear polarizers is attached at the entrance window of the telescope to induce a well known polarization into the telescope. A Muellar matrix model of the telescope to correct the obtained data is under examination. Title: Internal Fine Structure of Ellerman Bombs Authors: Hashimoto, Yuki; Kitai, Reizaburo; Ichimoto, Kiyoshi; Ueno, Satoru; Nagata, Shin'ichi; Ishii, Takako T.; Hagino, Masaoki; Komori, Hiroyuki; Nishida, Keisuke; Matsumoto, Takuma; Otsuji, Kenichi; Nakamura, Tahei; Kawate, Tomoko; Watanabe, Hiroko; Shibata, Kazunari Bibcode: 2010PASJ...62..879H Altcode: We conducted coordinated observations of Ellerman bombs (EBs) between Hinode Satellite and Hida Observatory (HOP12). CaII H broad-band filter images of NOAA 10966 on 2007 August 9 and 10 were obtained with the Solar Optical Telescope (SOT) aboard the Hinode Satellite, and many bright points were observed. We identified a total of 4 bright points as EBs, and studied the temporal variation of their morphological fine structures and spectroscopic characteristics. With high-resolution CaII H images of SOT, we found that the EBs, thus far thought of as single bright features, are composed of a few of fine subcomponents. Also, by using Stokes I/V filtergrams with Hinode/SOT, and CaII H spectroheliograms with Hida/Domeless Solar Telescope (DST), our observation showed: (1) The mean duration, the mean width, the mean length, and the mean aspect ratio of the subcomponents were 390 s, 170 km, 450 km, and 2.7, respectively. (2) Subcomponents started to appear on the magnetic neutral lines, and extended their lengths from the original locations. (3) When the CaII H line of EBs showed the characteristic blue asymmetry, they are associated with the appearance or re-brightening of subcomponents. Summarizing our results, we obtained an observational view that elementary magnetic reconnections take place one by one successively and intermittently in EBs, and that their manifestation is the fine subcomponents of the EB phenomena. Title: Spicule Dynamics over a Plage Region Authors: Anan, Tetsu; Kitai, Reizaburo; Kawate, Tomoko; Matsumoto, Takuma; Ichimoto, Kiyoshi; Shibata, Kazunari; Hillier, Andrew; Otsuji, Kenichi; Watanabe, Hiroko; Ueno, Satoru; Nagata, Shin'ichi; Ishii, Takako T.; Komori, Hiroyuki; Nishida, Keisuke; Nakamura, Tahei; Isobe, Hiroaki; Hagino, Masaoki Bibcode: 2010PASJ...62..871A Altcode: 2010arXiv1002.2288A We studied spicular jets over a plage area and derived their dynamic characteristics using Hinode Solar Optical Telescope (SOT) high-resolution images. A target plage region was near to the west limb of the solar disk. This location permitted us to study the dynamics of spicular jets without any overlapping effect of spicular structures along the line of sight. In this work, to increase the ease with which we could identify spicules on the disk, we applied the image processing method `MadMax' developed by Koutchmy et al. (1989). It enhances fine, slender structures (like jets), over a diffuse background. We identified 169 spicules over the target plage. This sample permited us to derive statistically reliable results regarding spicular dynamics. The properties of plage spicules can be summarized as follows: (1) In a plage area, we clearly identified spicular jet features. (2) They were shorter in length than the quiet region limb spicules, and followed a ballistic motion under constant deceleration. (3) The majority (80%) of the plage spicules showed a cycle of rise and retreat, while 10% of them faded out without a complete retreat phase. (4) The deceleration of the spicule was proportional to the velocity of ejection (i.e., the initial velocity). Title: Comparison of the Vector Magnetograms taken with the SFT/MTK and the SST/KSW Authors: Hagino, M.; Nakatani, Y.; Ishii, T. T.; Hanaoka, Y.; Sakurai, T.; Hiei, E.; Suzuki, D. Bibcode: 2009ASPC..405..393H Altcode: We carried out a detailed comparison between the vector magnetograms obtained with the Solar Flare Telescope (SFT/MTK) of the National Astronomical Observatory of Japan and those obtained with the Sextuple Solar Telescope (SST/KSW) of the Kawaguchi Science Museum (the former name is the Kawaguchi Science World). We investigated various characteristics of the errors in the Stokes parameters for each instrument. The level of noise due to seeing effects in the SST/KSW magnetograms is higher than in the SFT/MTK magnetograms. On the other hand, we found that about 60% of the data pixels have the same sign of current helicity α in these magnetograms. We will discuss the possibility and limitations of the magnetic field studies using these magnetograms. Title: Local Twist and Current Helicity Distributions of Active Region NOAA 10930 Authors: Su, J. T.; Sakurai, T.; Suematsu, Y.; Hagino, M.; Liu, Yu Bibcode: 2009ApJ...697L.103S Altcode: Hinode high-quality vector magnetograms and G-band data are utilized to study the distributions of local twist α z and current helicity hc on the active region of NOAA 10930. The new findings are as follows. (1) The patches of positive and negative helicities were intermixed showing a mesh pattern in the umbra and a thread pattern in the penumbra. (2) For its main stable sunspot (MSS), there was a positive-helicity patch accounting for ~43% of the umbra area surrounding the inner umbra, which had a predominantly negative helicity. For its minor rotating sunspot (MRS), there was a negative-helicity patch appearing in the umbra. (3) The fine distributions of α z and hc on a penumbral filament indicated that it may be possible for the two opposite helicities to coexist in a filament and their magnitudes were nearly equivalent. Title: Spectropolarimetric Observation of an Emerging Flux Region: Triggering Mechanisms of Ellerman Bombs Authors: Watanabe, H.; Kitai, R.; Okamoto, K.; Nishida, K.; Kiyohara, J.; Ueno, S.; Hagino, M.; Ishii, T. T.; Shibata, K. Bibcode: 2008ApJ...684..736W Altcode: 2008arXiv0805.4266W A high spatial resolution observation of an emerging flux region (EFR) was made using a vector magnetograph and a Hα Lyot filtergraph with the Domeless Solar Telescope at Hida Observatory on 2006 October 22. In Hα wing images, we could see many Ellerman bombs (EBs) in the EFR. Observations in two modes, slit scan and slit fixed, were performed with the vector magnetograph, along with the Hα filtergraph. Using the Hα wing images, we detected 12 EBs during the slit scan observation period and 9 EBs during the slit fixed observation period. With the slit scan observation, we found that all the EBs were distributed in the area where the spatial gradient of vertical field intensity was large, which indicates the possibility of rapid topological change in the magnetic field in the area of EBs. With the slit fixed observation, we found that EBs were distributed in the areas of undulatory magnetic fields, in both the vertical and horizontal components. This paper is the first to report the undulatory pattern in the horizontal components of the magnetic field, which is also evidence for emerging magnetic flux triggered by the Parker instability. These results allow us to confirm the association between EBs and emerging flux tubes. Three triggering mechanisms for EBs are discussed with respect to emerging flux tubes: 9 out of 21 EBs occurred at the footpoints of emerging flux tubes, 8 occurred at the top of emerging flux tubes, and 4 occurred in the unipolar region. Each case can be explained by magnetic reconnection in the low chromosphere. Title: On the Solar Cycle Variation of the Hemispheric Helicity Rule Authors: Pevtsov, A. A.; Canfield, Richard C.; Sakurai, T.; Hagino, M. Bibcode: 2008ApJ...677..719P Altcode: We study the statistical significance of observed temporal variations of the solar active-region hemispheric helicity rule, as measured by the latitudinal gradient of the best-fit linear force-free-field parameter, dα/dvarphi . Using data from four different vector magnetographs, we compute and compare average annual dα/dvarphi values for these instruments for 19 years from solar cycles 21, 22, and 23. We find that although every instrument shows the "wrong" sign for the hemispheric rule in some years, there is no agreement among the instruments on which years are abnormal. None of the four data sets shows annual values of dα/dvarphi departing from the hemispheric helicity rule by more than 3 σ. We conclude that because the hemispheric helicity rule is a weak tendency with significant scatter, an annual subset of active regions is likely to produce statistically unreliable results. Title: Magnetic Causes of the Eruption of a Quiescent Filament Authors: Schmieder, B.; Bommier, V.; Kitai, R.; Matsumoto, T.; Ishii, T. T.; Hagino, M.; Li, H.; Golub, L. Bibcode: 2008SoPh..247..321S Altcode: 2007SoPh..tmp..213S During the JOP178 campaign in August 2006, we observed the disappearance of our target, a large quiescent filament located at S25°, after an observation time of three days (24 August to 26 August). Multi-wavelength instruments were operating: THEMIS/MTR ("MulTi-Raies") vector magnetograph, TRACE ("Transition Region and Coronal Explorer") at 171 Å and 1600 Å and Hida Domeless Solar telescope. Counter-streaming flows (+/−10 km s−1) in the filament were detected more than 24 hours before its eruption. A slow rise of the global structure started during this time period with a velocity estimated to be of the order of 1 km s−1. During the hour before the eruption (26 August around 09:00 UT) the velocity reached 5 km s−1. The filament eruption is suspected to be responsible for a slow CME observed by LASCO around 21:00 UT on 26 August. No brightening in Hα or in coronal lines, no new emerging polarities in the filament channel, even with the high polarimetry sensitivity of THEMIS, were detected. We measured a relatively large decrease of the photospheric magnetic field strength of the network (from 400 G to 100 G), whose downward magnetic tension provides stability to the underlying stressed filament magnetic fields. According to some MHD models based on turbulent photospheric diffusion, this gentle decrease of magnetic strength (the tension) could act as the destabilizing mechanism which first leads to the slow filament rise and its fast eruption. Title: Skew Angle and Magnetic Helicity in Solar Active Regions Authors: Hagino, M.; Moon, Y. -J.; Sakurai, T. Bibcode: 2007ASPC..369..163H Altcode: The skew angle and magnetic helicity are important quantities in understanding the magnetic structures in solar active regions. Using Yohkoh/SXT images and vector magnetograms from the Solar Flare Telescope at Mitaka for 106 active regions, we have made the first attempt to examine the relationship between the skew angle and magnetic helicity. The skew angle is defined as the angle between the coronal loop and the line perpendicular to the polarity inversion line. We found that an active region having a large skew angle tends to have a large helicity value. This result implies that while a coronal loop with strong twist is nearly parallel to the axis of the polarity inversion line, a coronal loop with weak twist is perpendicular to the polarity inversion line, like a potential field structure. Title: SMART Observation of Magnetic Helicity in Solar Filaments Authors: Hagino, M.; Kitai, R.; Shibata, K. Bibcode: 2006IAUJD...3E..60H Altcode: We examined the magnetic helicity of solar filaments from their structure in the chromosphere and corona. The H-alpha telescope of the Solar Magnetic Activity Research Telescope (SMART) observed 239 intermediate filaments from 2005 July 1 to 2006 May 15. The intermediate filament usually locates between two active regions. Using these images, we identified the filament spine and its barbs, and determined the chromospheric filament helicity from the mean angle between each barbs and a spine. We found that 71% (78 of 110) of intermediate filaments in the northern hemisphere are negative helicity and 67% (87 of 129) of filaments in the southern hemisphere are positive, which agreed with the well-known hemispheric tendency of the magnetic helicity. Additionally, we studied the coronal helicity of intermediate filaments. The coronal filament helicity is defined as the crossing angle of threads formed a filament. The helicity pattern of coronal filaments obtained with EIT/SOHO 171A also shows the helicity hemispheric tendency. Namely, 65% (71 of 110) of coronal filaments in the northern hemisphere exhibit negative helicity and the 65% (84 of 129) of filaments in the southern hemisphere show negative helicity. These data were observed in the same day with the SMART H-alpha data. Moreover, we found 12 filament eruptions in our data. The 7 of 12 filaments show the clear opposite sign of the hemispheric tendency of the magnetic helicity. The helicity seems to be change during temporal evolution. This results suggest that filament instability may be driven by the opposite sign helicity injection from the foot point of the barb. Title: Solar-Cycle Variation of Magnetic Helicity in Active Regions Authors: Hagino, Masaoki; Sakurai, Takashi Bibcode: 2005PASJ...57..481H Altcode: The hemispheric sign rule of helicity and its long-term variation were studied. The data were obtained from the Solar Flare Telescope at Mitaka and the 65-cm solar telescope at Okayama. The data covered the period of 1983-2001, from the declining phase of solar cycle 21 to the rising phase of cycle 23. Although the hemispheric sign rule of helicity generally holds, we also found significant time variations in the yearly values of helicity during the observation period. The hemispheric sign rule of helicity is satisfied in the solar maximum phase, but may not be so in the solar minimum phase. Title: Spectroscopic Studies of Solar Corona VII. Formation of a Coronal Loop by Evaporation Authors: Singh, Jagdev; Sakurai, Takashi; Ichimoto, Kiyoshi; Suzuki, Isao; Hagino, Masaoki Bibcode: 2005SoPh..226..201S Altcode: We obtained time-sequence spectroscopic observations in (Fe X) 6374 Å and (Fe XIV) 5303 Å lines successively with the 25-cm coronagraph, and narrow-band and Doppler images in 5303 Å line by the 2-D 10-cm Doppler coronagraph "NOGIS" at the Norikura Solar Observatory, of a coronal region for about 7 h on 9 19-20, 2001. The raster scans were obtained with a quasi-periodicity of about 14 min and "NOGIS" obtained the images with an interval of about 1 min. The coronal region observed showed the formation of a coronal loop by a high-speed surge in the 6374 Å line rising from one of the footpoints of the loop. Off the limb spectroscopic observations in the 6374 Å line showed large velocities along the line of sight and vertical to the solar limb at the time of formation of the loop. The 5303 Å line observations showed negligible line-of-sight velocities and low vertical velocities when compared to those in the 6374 Å line. A hump in the intensity plots in 5303 Å with height appears to move up with respect to the solar limb with an average velocity of 4km s−1. The FWHM of the 6374 Å showed a much smaller value of about 0.7 Å near the foot point as compared to a value of 1.2 Å at larger heights at the beginning of observations. Later as the loop developed, the FWHM of 6374 Å line showed a gradual decrease along the loop up to 70″ from the limb, reached a minimum value of about 0.5 Å and then increased with height during the formation of the loop; this trend lasted for about 2 h. About 3 h after the beginning of the formation of the loop, the FWHM of 6374 Å emission line showed normal values and normal rate of increase with height with some fluctuations. The FWHM of the 5303 Å line did not show such variations along the loop and showed normal decrease in FWHM with height found earlier (Singh et al., 2003a). These observations suggest that a relatively cooler plasma at a temperature of about 0.7 MK or less (corresponding to minimum value of FWHM of 0.5 Å) was ejected from the transition region with a large velocity of about 48km s−1, heated up in the corona by some process and formed a coronal loop with a height of about 200″ above the limb that had lifetime greater than 4 h. It appears that the plasma moved from one of the footpoints and the loop was formed by evaporation of chromospheric plasma. No large-scale brightening and Hα flare were observed in this region during the observational period of 7 h. Title: Hemispheric sign rule of magnetic helicity on the Sun Authors: Hagino, Masaoki; Sakurai, Takashi Bibcode: 2005ARAOJ...7...49H Altcode: No abstract at ADS Title: On a Cyclic Variation of the Hemispheric Helicity Rule Authors: Pevtsov, A. A.; Hagyard, M. J.; Blehm, Z.; Smith, J. E.; Canfield, R. C.; Sakurai, T.; Hagino, M. Bibcode: 2005HiA....13..140P Altcode: We report the result of a study of magnetic helicity in solar active regions during 1980-2000 (cycles 21-23). Using the vector magnetograms from four different instruments (Haleakala Stokes Polarimeter Marshall Space Flight Center Mitaka Solar Flare Telescope and Okayama Observatory Solar Telescope) we calculated the force-free parameter alpha as in Pevtsov et al. (1995). We use alpha as the proxy for current helicity. For each instrument we computed a gradient dalpha/dL as the linear fit of alpha versus latitude L using annual subsets of data. The hemispheric helicity rule (negative/positive helicity in northern/southern hemisphere) can be expressed in terms of this gradient as dalpha/dL < 0. We find that each instrument exhibits change in sign of this gradient for some years which implies that the hemispheric helicity rule may not hold in some phases of a solar cycle (see Hagino and Sakurai 2002). However we do not see consistency between different instruments in regards to years disobeying the rule. The disagreement may be due to difference in observations and/or insufficient number of magnetograms in some years. We conclude that the present data sets do not allow to make statistically significant inference about possible cyclic variation of the hemispheric helicity rule. Title: Phase Relationship between the Activity Cycles of Sunspots and Polar Faculae Authors: Hagino, M.; Sakurai, T.; Miyazawa, A. Bibcode: 2004ASPC..325..157H Altcode: The eleven-year activity cycles of polar faculae and sunspots are out of phase by half a cycle. We studied the phase relationship between the cycles of sunspots and polar faculae, by using the data of sunspot and facular numbers obtained at Mitaka in the period of 1952--1998 (47 years, four sunspot cycles). We applied the cross-correlation analysis and wavelet phase differences, and found that the phase relationship was not persistent. The polar faculae were better correlated with the sunspots of the previous cycle over two sunspot cycles of 1964--1987, while the reverse was the case if the data of the whole four cycles were used. Title: Latitude Variation of Helicity in Solar Active Regions Authors: Hagino, Masaoki; Sakurai, Takashi Bibcode: 2004PASJ...56..831H Altcode: We studied the current helicity of 230 active regions on the Sun during the period of 1992-2001. Vector magnetograms used were obtained with the Solar Flare Telescope, located at the Mitaka campus of the National Astronomical Observatory. The latitude distribution of helicity shows a negative slope; namely, the regions in the northern (southern) hemisphere tend to show a negative (positive) helicity, respectively, in agreement with previous studies. The scatter seen in the helicity is significantly larger than expected from the measurement errors, implying that the process generating the helicity is of random, turbulent nature. Therefore, convective motion must play an essential role in generating the helicity of active regions. Title: Existence of Nanoparticle Dust Grains in the Inner Solar Corona? Authors: Singh, Jagdev; Sakurai, Takashi; Ichimoto, Kiyoshi; Hagino, Masaoki; Yamamoto, Tetsuya T. Bibcode: 2004ApJ...608L..69S Altcode: Motivated by the recent paper by Habbal et al., we have made spectroscopic observations in the wavelength range of 1072.8-1079.0 nm of the solar corona above the coronal hole region on several days using a coronagraph. We made raster scans above the coronal hole region as well as other coronal regions for comparison. The exposure time of 200 s at a single location permitted us to detect signals of the order of 10-7 of the solar disk brightness. We did not find any indication of emission around 1074.7 nm due to fluorescence from silicon nanoparticle dust grains in the coronal hole region in the inner corona proposed by Habbal et al. This may be due to the absence of silicon nanoparticle dust grains in the coronal hole region or to our detection limit. Title: Loading of magnetic helicity and flare activity Authors: Hagino, M.; Yamamoto, T.; Sakurai, T. Bibcode: 2004cosp...35.1955H Altcode: 2004cosp.meet.1955H Studies of twisted flux tubes are important in understanding the mechanisms of solar flares and coronal mass ejection. In this study, we have made a comparison between the helicity injection rate Hin and the force-free parameter α. The latter is an indicator of accumulated helicity. The magnetograms we used were obtained with SOHO/MDI and with the Solar Flare Telescope (SFT) of NAOJ in Mitaka, Tokyo. SFT can take vector magnetograms every 3 minutes. To measure the helicity injection, we have employed Kusano's method (Kusano et al. 2002) which can derive the helicity injection due to both shearing motion and emerging motion. We studied several active regions which produced major flares (for instance, NOAA 9661). We estimated the values of Hin and α in two ways; (1) by averaging over the whole region and (2) by isolating the flare area. In the case of NOAA 9661, a GOES X1.7 class flare was observed on 2001 October 19. The value of α averaged over the whole region was negative, which agreed with the hemispheric helicity sign rule because this region appeared in the northern hemisphere. If the area of 100'' × 50'' near the flare neutral line was selected, we found the following results. (1) The temporal changes in α were consistent with the variations in Hin. (2) No emerging flux activity was seen, and the contributions to Hin from the emerging motion were small. (3) The pixel to pixel correlation between Hin and α in the area showed a positive correlation before the flare. After the flare the correlation weakened. Property (3) may imply that the magnetic helicity is being loaded prior to the flare. Therefore, the correlation between Hin and α can be used as an indicator of energy build-up process. Title: The flare of 1991 June 4 (importance 3B) and the associated Moreton wave Authors: Yamaguchi, Kisuke; Sakurai, Takashi; Irie, Makoto; Kumagai, Kazuyoshi; Hagino, Masaoki; Miyashita, Masakuni; Shiomi, Yasuhiko; Hiei, Eijiro Bibcode: 2003RNAOJ...6..101Y Altcode: We observed a Moreton wave associated with a flare of importance 3B in the NOAA region 6659 on 1991 June 4. The Moreton wave was emitted from a flare bright point and initially showed the form of a loop. The speed of the Moreton wave was initially 1500 km s-1 and was later accelerated to 1800 km s-1. This acceleration may be due to the propagation of the wave into a coronal hole (with low density and high Alfvén velocity. Title: Magnetic Helicity of Solar Active Regions and its Implications Authors: Sakurai, T.; Hagino, M. Bibcode: 2003JKAS...36S...7S Altcode: No abstract at ADS Title: On a Cyclic Variation of the Hemispheric Helicity Rule. Authors: Pevtsov, Alexei A.; Hagyard, Mona J.; Blehm, Zachary; Smith, James E.; Canfield, Richard C.; Sakurai, Takashi; Hagino, Masaoki Bibcode: 2003IAUJD...3E..35P Altcode: We report the result of a study of magnetic helicity in solar active regions during 1980-2000 (cycles 21-23). Using the vector magnetograms from four different instruments (Haleakala Stokes Polarimeter Marshall Space Flight Center Mitaka Solar Flare Telescope and Okayama Observatory Solar Telescope) we calculated the force-free parameter alpha as in Pevtsov et al. (1995). We use alpha as the proxy for current helicity. For each instrument we computed a gradient dalpha/dL as the linear fit of alpha versus latitude L using annual subsets of data. The hemispheric helicity rule (negative/positive helicity in northern/southern hemisphere) can be expressed in terms of this gradient as dalpha/dL < 0. We find that each instrument exhibits change in sign of this gradient for some years which implies that the hemispheric helicity rule may not hold in some phases of a solar cycle (see Hagino and Sakurai 2002). However we do not see consistency between different instruments in regards to years disobeying the rule. The disagreement may be due to difference in observations and/or insufficient number of magnetograms in some years. We conclude that the present data sets do not allow to make statistically significant inference about possible cyclic variation of the hemispheric helicity rule. Title: Magnetic helicity and flare activity Authors: Sakurai, T.; Hagino, M. Bibcode: 2003AdSpR..32.1943S Altcode: We studied two active regions appeared in 2001 (NOAA 9415 and 9661), both of which have produced X-class flares. The time evolutions of magnetic flux and magnetic helicity were derived based on vector magnetograph observations. These regions satisfied the so-called hemispheric rule of magnetic helicity, namely regions in the northern (southern) hemisphere tend to have negative (positive) helicity. The magnetic helicity integrated over the regions evolved slowly and did not show abrupt changes at the time of the flares, although the distributions of magnetic helicity changed significantly over a few days in the regions. The appearance of localized regions whose helicity was opposite to that expected from the hemispheric rule was seen in both cases. Title: Hemispheric Helicity Asymmetry in Active Regions for Solar Cycle 21-23 Authors: Hagino, M.; Sakurai, T. Bibcode: 2002mwoc.conf..147H Altcode: Magnetic helicity observed at the surface carries information on the invisible, sub-surface processes such as internal rotation and the behavior of magnetic flux tubes in the convection zone. It has been recognized that magnetic helicity shows a hemispheric rule; the northern (southern) hemisphere tends to show negative (positive) helicity. It is also known that this rule does not change with solar cycle. The determination of the helicity, requiring vector magnetograms, is sensitive to various noises and instrumental effects, and is therefore not an easy task. Considering the importance of magnetic helicity, here we present the results based on our data set and compare them with results from other observatories. We analyzed vector magnetograms in the period of 1992-2000 obtained with the Solar Flare Telescope at the National Astronomical Observatory of Japan. The current helicity was determined by two methods for 180 active regions. The first method calculates the electric currents over active regions by a direct differentiation and then evaluates the average helicity, alpha = frac sum (abla times vec {B})zcdot {m sign} (Bz) + Bz. The second method is the fitting of the linear force-free field vec{B}m cal (alpha) to the observed transverse field vec{B}m obs and finds the best-fit alpha which minimizes frac sum [vec{B}m cal(alpha) - vec{B}m obs]2 sum Bm obs2. The data points with transverse fields larger than 150 G (noise level) and with longitudinal fields weaker than 500 G were used. The latter condition was to minimize the effect of Faraday rotation that may change the azimuth of the transverse field. We plotted the helicity against solar latitude and calculated a linear fit to the data. The slopes of the fit obtained from the first and the second methods are (-1.08 ± 0.51) times 10-10 mm-1 m deg-1 and (-3.30 ± 1.14) times 10-10 mm-1 m deg}-1, respectively. Our results agree with the previous studies and confirm the hemispheric rule. Title: A Flexible Prism used as an Image Stabilizer Authors: Sakurai, T.; Noguchi, M.; Shinoda, K.; Tanaka, N.; Aoki, K.; Hagino, M.; Mochizuki, H. Bibcode: 2002SoPh..205..201S Altcode: An image stabilizer was constructed by making use of a flexible prism, which is widely used as an anti-vibration mechanism in handheld video cameras. The prism responds to frequencies up to 20 Hz, and can be simply inserted into existing optics. The performance of the prism has been confirmed by observing the Sun through it. Title: Magnetic helicity and flare activity Authors: Sakurai, T.; Hagino, M. Bibcode: 2002cosp...34E2093S Altcode: 2002cosp.meetE2093S We studied two active regions appeared in 2001 (NOAA 9415 and 9661), both of which have produced X-class flares. Time evolutions of magnetic flux and magnetic helicity were derived based on vector magnetograph observations. These regions obey the so-called hemispheric rule of magnetic helicity, namely regions in the northern (southern) hemisphere tend to have negative (positive) helicity. The magnetic helicity showed slow evolution but did not show abrupt changes at the time of flares. Flare activity was correlated with changes in the distributions of magnetic helicity that were driven by horizontal flows.