Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for the month of February 1994) ABSTRACT The SOLAR-A Mission is a program of the Institute of Space and Astronautical Science (ISAS), the Japanese agency for scientific space activity. The SOLAR-A satellite was launched on August 30, 1991 from Kagoshima Space Center (KSC) in Japan, and renamed Yohkoh. The purpose of this mission is to study high energy phenomena in solar flares. Under an international cooperative agreement, Lockheed, under NASA contract, is providing a scientific investigation using the Soft X-ray Telescope (SXT), one of the primary experiments of the mission. The SXT was developed by Lockheed in cooperation with the National Astronomical Observatory of Japan, and the Institute for Astronomy of the University of Tokyo. MAJOR PROGRAMMATIC ACTIVITIES IN THE MONTH Acton received the good news that NASA does not plan to terminate Yohkoh operations at the end of 3 years. FY '95 funds to continue the mission are in the proposed budget to Congress. We are reviewing the implications of another year's operations in Japan in terms of both staffing and scientific objectives. The new baseline entails one year of operations after FY '94, and then one year of data analysis in FY '96. << Solar Activity >> Solar activity has declined from the relatively active levels of December and January, but the Sun did produce two M-class long-duration events in the last week of the month. The active region that produced these events has now returned four times and is still producing large flares. The main thrust of our observations have been filaments, coronal holes, and X-ray bright points. There has been a large number of these objects available, and with the lower level of activity SXT can afford to take much deeper exposures of them. The apparent simplification of the corona is also making the study of even small-scale emerging flux regions more interesting because SXT can now observe them in a less complex environment. Active regions 7669, 7670 and 7671 have produced some very interesting loop activity but very little flaring. This is a large complex and will be useful for study of coronal heating in and around regions of little flare activity. Page 2 << Observation Planning >> Observation planning was primarily done by H. Hudson and L. Acton this month. SXT operations activities generally consisted of the regular weekly dark-current calibrations, the offpoints, and table uploads for the terminator image acquisition program. A special table was uploaded to obtain full-resolution diffuser images. Deep exposure FFI observing was tried in support of the request by the SPARTAN team who are looking for polar rays, these data are also good practice for Ulysses and SOHO support over the next few years. A special SXT flare table was built to obtain calibration data on x-ray scattering by the ND filter. << Campaigns >> 1.The GBO campaign with Habbal at SPO and Lika on the Mk III coronagraph was mostly a failure as SPO was in bad weather. Data were acquired at the Mk III and it is planned to compare these to SXT images in further studies with M. Guhathakurta on coronal rays observed in electron scattered white light and x-rays. 2.Karen Harvey proposes another XBP campaign beginning 8-Mar-94. Acton will be the campaign coordinator. << Science Progress>> A mini-workshop was held at ISAS on 9-Feb-94 on campaign observations. The primary focus of the meeting was the worldwide campaign to observe emerging flux regions which took place last August. Unfortunately, observing conditions at the Japanese observatories were unusually poor--a typhoon came through in the middle of the campaign--so that full benefit was not obtained. None the less, some useful coordinated observations were obtained and are being followed up. Hugh Hudson continues to work with the spectacular eruption/ejection of 21-Feb-92 (much like the 2-Dec-91 event studied by Tsuneta and Martens). The magnetic field topology of these things is, of course, not so simple at the old cartoons. Better cartoons should result in better physics. Acton begun a bit of work with Hara san to look at the radiative loses from different classes of coronal structures--with the objective of a paper on this at the AGU in Baltimore. With the decrease in solar activity we are increasingly interested in deep SXT exposures. The question is, how deep can we go before coronal changes, Page 3 solar rotation and instrumental artifacts become the limiting factor. This week I have been working with summed one minute full resolution exposures of the south half of the disk obtained in support of a ground-based observing campaign by Shadia Habbal at CFA and Madhulika Guhathakurta at GSFC. The statistical quality of the 240-s sums is exquisite and reveal instrumental artifacts in AlMg, a near horizontal set of lines across the brighter portions of the image, which we have never seen before. It is not yet clear to us whether these extremely deep exposures reveal more about the solar corona than somewhat shorter exposures--we may be up against the limit of our ability to correct for artifacts. Jack Gosling and Loretta Weise from JPL visited Lockheed to discuss bidirectional-directional electron streams observed by Ulysses. They are trying to identify the coronal signatures of these streams, which have often been associated with Coronal Mass Ejections. They spent two days working with Keith Strong glued to the SXT video disk comparing times of Ulysses events and projecting them back to the Sun. Unfortunately the uncertainties in this process are large and it was easy to to find events that might have been associated. We found several solid examples and quite a few mysteries. As the solar corona becomes less active and Ulysses sinks to higher southern latitudes it will become easier to make these associations. Most of our scientific efforts this month were focused on preparing and submitting abstracts for the upcoming AGU/SPD meeting in Baltimore. There were 48 papers and presentations in various stages of preparation and publication in February (including a few reported late from January) generated by members of the SXT team. -- Awards [3] -- Some nice happenings this month: First was the award of an SPD studentship to Brian Handy of Montana State to support attendance at the Baltimore meeting. Also, Masuda san and Sakao san both passed their PH.D. examinations based upon HXT analysis. -- Papers Submitted [8]-- "The Possible Role of MHD Waves in Heating the Solar Corona" by Porter, Klimchuk, and Sturrock, Astrophysical Journal "The Possible Role of High-Frequency Waves in Heating Solar Coronal Loops." by Porter, Klimchuk, and Sturrock, Astrophysical Journal Page 4 "The Magnetic Evolution of AR7260: A Roadmap", K. D. Leka, L. van Driel- Gesztelyi, N. Nitta, R. C. Canfield, D. L. Mickey, submitted to Solar Physics. "A Gigantic X-ray Jet observed by Yohkoh", K. Shibata, H. S. Hudson, et al., submitted to Nature. "A Diagnostic of Solar Atmospheric Models: Search for 'Black Flares'", L. van Driel-Gesztelyi, H.S. Hudson, B. Anwar, E. Hiei, and S. Tsuneta, submitted to Solar Physics. "Spatial Resolution of Solar Irradiance Variability: The Yohkoh White- Light Observations" H. S. Hudson, submitted to Proc. IAU Symposium #143 "The Yohkoh Soft X-ray Observations", H. S. Hudson, submitted to Proceedings of the Symposium "A New Look at the Sun", hold in Kofu, September 1993. "H-alpha and X-ray Signatures of Chromospheric Evaporation Observed during the Early Phase of the 15 November 1991 Flare" J.-P. Wuelser, R. C. Canfield, L. W. Acton, J. L. Culhane, A. Phillips, A. Fludra, T. Sakao, S. Masuda, and T. Kosugi, submitted to the Proceedings of the Symposium "A New Look at the Sun", hold in Kofu, September 1993. -- Papers Accepted for Publication [6]-- "The Violent Corona" by K. Strong, an invited article for Odyssey Magazine "Electric Currents and Coronal Heating in NOAA Active Region 6952", T. R. Metcalf, R. C. Canfield, H. S. Hudson, D. L. Mickey, J.-P. Wuelser, P. C. H. Martens, and S. Tsuneta, ApJ, in press, June 1994. "Electron Precipitation and Mass Motion in the 1991 June 9 White-Light Flare", J.-F. de La Beaujardiere, R. C. Canfield, T. R. Metcalf, E. Hiei, T. Sakurai, and K. Ichimoto, Solar Physics, in press, 1994. "Radio Imaging Observations of the Evolution of Thermal and Nonthermal Sources during a Gradual Burst", M. Nishio, H. Nakajima, S. Enome, K. Shibaski, T. Takano, Y. Hanaoka, C. Torii, H. Sekiguchi, T. Bushimata, S. Kawashima, N. Shinohara, Y. Iramajiri, Y. Choi, H. Koshiishi, Y. Shiomi, T. Metcalf, R. C. Canfield, PASJ, in press, 1994. "A Purely Polarized S-component at 17 GHz", K. Shibasaki, S. Enome, H. Nakajima, M. Nishio, T. Takano, Y. Hanaoka, C. Torii, H. Sekiguchi, S. Kawashima, T. Bushimata, N. Shinohara, H. Koshiishi, Y. Shiomi, Y. Irimajiri, K. D. Leka, and R. C. Canfield, PASJ, in press 1994. "High Energy Gamma Ray Emission from Solar Flares: Constraining the Proton Spectrum", D. Alexander, P.P. Dunphy and A.L. MacKinnon, Solar Physics. -- Papers Published [2] -- "Dynamics of the Solar Corona Observed with the Yohkoh Soft X-ray Telescope" by S. Tsuneta and J. Lemen, Page 5 'Physics of Solar and Stellar Coronae', eds J. Linsky and S. Serio, Kluwer, 1993 "Rapid Sunspot Motion during a Major Solar Flare", B. Anwar, L. W. Acton, H. S. Hudson, M. Makita, A. N. McClymont and S. Tsuneta, Solar Phys., 147, 287. - Presentations Given [7]-- "Current-carrying magnetic flux in emerging solar active regions", K. D. Leka, Harvard-Smithsonian Center for Astrophysics, 7 February 1994. "Current-carrying magnetic flux in emerging solar active regions", K. D. Leka, NASA/Goddard Space Flight Center, 15 February 1994. "Current-carrying magnetic flux in emerging solar active regions", K. D. Leka, NCAR/High Altitude Observatory, 17 February 1994. "Eclipses of the Solar X--ray Corona by Mercury and the Moon", H. Hudson, S. Freeland, T. Kosugi, J. Lemen, T. Shimizu, T. Watanabe, AAS, Washington, 10 Jan 1994 "Comments on the Solar-B Payload from the Point of View of Yohkoh Science", H. S. Hudson, Solar-B workshop, Mitaka, 24 Feb 1994 "Observational Studies of Magnetic Reconnection", R. C. Canfield, Department of Astronomy, Kyoto University, 4 Feb 1994. "Patterns of Helicity in Solar Active Regions", R. C. Canfield, Solar Division, NAOJ, Mitaka, 10 February 1994. -- Abstracts Submitted [25]-- "The Source Regions of CMEs and the Large-Scale Magnetic Field Using Yohkoh SXT Data," by Webb, Kahler, and Klimchuk, AGU/SPD "X-Ray Bright Points: The Signature of Magnetic Field Reconnection," Karen L Harvey, Frances Tang, Hal Zirin, Sara Martin, Hugh Hudson, Don Mickey, Marilyn Bruner, James Lemen, Keith Strong, Nariaki Nitta, and Saku Tsuneta, AGU/SPD "Coronal Fine Structure - Temperatures Estimated from NIXT and SXT," by Deluca, Strong, Golub, and Daw, AGU/SPD "Estimating Solar X-ray Forcing of the Middle Atmosphere from Yohkoh Data," Lean, Mariska, and Strong, AGU/SPD "Yohkoh and SPARTAN Observations of Large-Scale Page 6 Coronal Activity," Strong, Nitta, Hudson, Fisher, Guhathukurta, and Habbal, AGU/SPD "Stereoscopic Determination of Coronal Geometries Using SXT Data," Slater, Hudson, Freeland, and Strong, AGU/SPD "Coordinated SPDE Rocket, Yohkoh, and Ground Observations of an Emerging Flux Region and a Filament," Dame, Brown, Bruner, Shine, Tarbell, Strong, and Suemats, COSPAR "Comparison of Yohkoh and Ulysses Observations of Boundaries of High-Speed streams in the Solar Wind," Neugebauer, Strong, Linford, Slater, and Phillips, AGU/SPD "SERTS EUV Imaging Spectroscopy," Davilla, Thomas, and Strong, AGU/SPD "The Coronal Origin of a Magnetic Cloud in the Solar Wind and a new Type of Forward-Reverse Shock," Bame, Gosling, Phillips, Scime, Pizzo, Goldstein, Balogh, and Strong, AGU/SPD "The Structure of the Extended Corona: Comparison With Solar Wind Models," Lemen, Hudson, and Acton, AGU/SPD "Yohkoh-SXT Observations at Solar Minimum," Lemen, AGU/SPD "A Search for Low Energy Protons in Several Solar Flares from October, 1992" T. R. Metcalf, D. L. Mickey, R. C. Canfield, J.-P. Wuelser, T. Kosugi, and S. Tsuneta, for the Baltimore AGU/SPD meeting, May 1994. "Diagnostics of Current-Carrying Emerging Flux", K. D. Leka, R. C. Canfield, A. N. McClymont, T. R. Metcalf, for the Baltimore AGU/SPD meeting, May 1994. "The Timing and Energetics of an X-ray Mass Ejection in a Slow LDE Flare," H. S. Hudson, J. R. Lemen, and S. Tsuneta, for the Baltimore AGU/SPD meeting, May 1994. "Chromospheric Heating and Energetics in Three Large Flares," J.-P. Wuelser, R. C. Canfield, L. W. Acton, T. Kosugi, and J. L. Culhane, for the Baltimore AGU/SPD meeting, May 1994. "The Coronal Magnetic Field of Active Region 7260," A. N. McClymont, L. Jiao, and Z. Mikic, for the Baltimore AGU/SPD meeting, May 1994. "Coronal Loop Thickness Variations and Electric Currents," L. Jiao, R. C. Canfield, and J. A. Klimchuk, for the Baltimore AGU/SPD meeting, 1994 Page 7 "Patterns of Helicity in Solar Active Regions," A. A. Pevtsov, R. C. Canfield, and T. R. Metcalf, for the Baltimore AGU/SPD meeting, May 1994. "Connectivity and Currents in AR 7562," D. L. Mickey, K. D. Leka, and T. R. Metcalf, for the Baltimore AGU/SPD meeting, May 1994. "X-ray Jets and H-alpha Surges in AR 7260," R. C. Canfield, K. D. Leka, K. P. Reardon, K. Shibata, M. Shimojo, and T. Yokoyama, for the Baltimore AGU/SPD meeting, May 1994. "X-ray Studies of the Solar Corona by Yohkoh", L.W. Acton (invited talk) for the Baltimore AGU/SPD meeting, May 1994. "Radiative Energy Losses of the Solar Corona", L.W. Acton, H. Hara and M.D. Morrison (contributed talk) for the Baltimore AGU/SPD meeting, May 1994. "Creation and Heating of Inter-region Loops", B.N. Handy, L.W. Acton, D. Alexander, T.R. Metcalf, H.S. Hudson and T. Shimizu (contributed talk) for the Baltimore AGU/SPD meeting, May 1994. "Non-thermal soft X-ray line broadening in gamma-ray flares", D. Alexander and S.A. Matthews. COSPAR << Public Use of SXT Images >> G. Linford and K. Strong produced another in a continuing series articles on solar activity for Sky & Telescope. This is the third such article to be published featuring SXT images. We continue to receive many requests for the SXT posters, public relations prints, and video tapes for educational purposes. Two versions of our PR video tapes have been sent to WGBH in Boston to follow up on an inquiry about an edition of "Nova" on the Sun. << Computer Software and Hardware >> Gary Linford put several long days into unsuccessfully trying to get the latest UNIX System installed on ISASS4. << Spacecraft and SXT Operations and Health >> Yohkoh and SXT continue to function well. No major subsystem has failed in the first 30 months of operation. All other Yohkoh instruments continue to produce scientifically interesting data. Acton has carefully checked recent CCD dark frames and calculate that, at the rate of increase in dark signal observed over the past 6 months it will take 5 years for the dark signal to double. This would leave it still well within a usable range so we plan to make an SXT movie that covers an entire solar cycle! Several DSN passes were canceled on short notice due to NASA support for the DPSE and Shuttle missions. During recent operations both the BCS and SXT have experienced a nominal level of single event upsets (SEUs). The SXT SEUs were found: Page 8 Found at: Recovery at: Error: 940208-0274 Same pass Bit map error 940209-0514 Same pass Bit map error Several false flare flags associated with SAA exit (a temporary problem that happens when the Yohkoh apogee falls in the SAA) were noted throughout the month. In the course of examining recent SXT visible light diffuser images Acton discovered that the solar image area was covered with tiny specks. Full resolution diffuser images were acquired and it is found that these specks are about 20 DN deep and are usually 1-3 pixels in extent. The origin of these specks is being investigated. Page 9 << Data Flow >> There was a data transfer problem between JPL and ISAS that began at an unfortunate time for prompt local response so a 54-contact backlog was created at JPL that may have to be transferred on tape. This may in turn put the Yohkoh reformatting somewhat behind. ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Sep-91 517 397 21174 3541 24715 5481 18.15 Oct-91 4106 2532 6393 12437 18830 3401 15.30 Nov-91 5291 2475 12149 14696 26845 10952 28.98 Dec-91 4896 3190 5001 16837 21838 6892 23.99 Jan-92 5544 3177 10084 5972 16056 6849 29.90 Feb-92 5305 2803 16932 11382 28314 12019 29.80 Mar-92 6248 2361 20367 2653 23020 9458 29.12 Apr-92 6734 3500 20094 5423 25517 12390 32.69 May-92 7032 3158 25464 4589 30053 13745 31.38 Jun-92 7230 2819 24375 13361 37736 11419 23.23 Jul-92 6345 3275 23944 10510 34454 14714 29.93 Aug-92 6572 2978 24207 11154 35361 13550 27.70 Sep-92 6087 2916 26832 20042 46874 15729 25.12 Oct-92 6743 2589 50985 14709 65694 23687 26.50 Nov-92 6658 2939 24416 14696 39112 12924 24.84 Dec-92 6747 3027 24147 6600 30747 12495 28.90 Jan-93 6888 3351 24067 4861 28928 13069 31.12 Feb-93 6833 3004 24479 18149 42628 12302 22.40 Mar-93 7177 3460 25874 19537 45411 14657 24.40 Apr-93 7754 3644 34128 8352 42480 17967 29.72 May-93 8571 3950 41832 7518 49350 21971 30.81 Jun-93 7340 2589 64545 12539 77084 26299 25.44 Jul-93 8259 3650 47561 5352 52913 24213 31.39 Aug-93 7628 3638 30705 3563 34268 17436 33.72 Sep-93 6875 2899 22697 5600 28297 11252 28.45 Oct-93 7474 3657 33782 7548 41330 20104 32.72 Nov-93 8353 4015 42180 5849 48029 24669 33.93 Dec-93 5898 3047 21128 13297 34425 13001 27.41 Jan-94 6934 2804 28567 10960 39527 13746 25.80 Feb-94 2856 1110 9217 3617 12834 4523 26.06 Total 190895 88954 787326 295344 1082670 420914 27.99 Number of Full Frame Images Received: 190895 Number of Observing Region Images Received: 1082670 Total: 1273565 Approximate Number of Shutter Moves/CCD Readouts: 2249147 NOTES: * The loss of images is mainly due to BDR overwrites, but there are also occasional DSN dumps which are lost. * It is common to have observing regions which contain more than 64 lines, which requires multiple exposures to make a single observing region image. This is why the number of shutter moves is larger than the number of images received plus those lost. Page 10 << Engineering Summary Table >> ------------------------------------------------------------------------------- Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) Oct-91 31.07 21.3 509 261 10.5 77.8 Nov-91 31.06 20.9 648 277 11.9 64.4 Dec-91 31.04 20.2 804 353 14.0 52.5 Jan-92 31.13 23.6 985 450 0.5 / 2 14.9 38.4 Feb-92 31.32 30.8 1176 544 14.3 31.7 Mar-92 31.47 36.5 1355 626 14.8 25.1 Apr-92 31.44 35.2 1323 610 23.8 / 4 14.6 22.8 May-92 31.65 43.1 1417 653 14.4 20.1 Jun-92 32.12 60.9 2215 880 -2.5 / 3 15.1 17.4 Jul-92 32.19 63.2 1829 822 15.5 14.1 Aug-92 32.21 64.1 1922 886 14.9 13.1 Sep-92 32.38 70.5 2062 954 -1.2 / 3 15.9 12.2 Oct-92 32.64 80.3 2317 1055 16.8 11.5 Nov-92 36.24 215.1 6112 1391 18.0 11.0 Dec-92 42.58 452.8 17390 2024 17.9 N/A Jan-93 42.59 453.1 13006 2034 23.8 / 2 19.2 N/A Feb-93 42.28 441.5 13895 2090 17.7 N/A Mar-93 43.14 473.8 14047 2151 17.7 N/A Apr-93 43.13 473.4 14304 2146 23.8 / 2 16.9 N/A May-93 43.45 485.3 16405 2357 17.3 N/A Jun-93 44.03 507.2 20037 2531 16.3 N/A Jul-93 44.52 525.6 23977 2700 22.5 / 2 17.7 N/A Aug-93 44.24 515.0 21879 2643 25.2 / 3 17.2 N/A Sep-93 45.07 546.2 27469 2745 17.5 N/A Oct-93 45.40 558.6 31684 2982 17.7 N/A Nov-93 45.31 554.9 31892 3224 23.8 / 3 19.7 N/A Dec-93 45.92 578.1 38515 3101 19.2 N/A Jan-94 46.18 587.9 42560 3464 22.5 / 2 20.3 N/A Feb-94 46.13 585.7 41198 3207 18.9 N/A NOTES: * The dark current calculations are using full half resolution 2.668-s images not taken in during the SAA. The dark current rate assumes a "fat zero" of 30.5 DN and a gain of 100 e/DN. * The entrance filter failure of 13-Nov-92 eliminated the capability of taking optical images, so the optical transmission is not available after Nov-92. It also caused an increase in the dark current signal, however some of the increase shown here is an increase in the read-out noise and is not a function of exposure duration. Page 11 << Personnel Travel >> -- SXT travel for the month of February 1994: -- ACTON 1-FEB-94 * 1-MAR-94 * 29 (total of 29 days) HUDSON 1-FEB-94 * 1-MAR-94 * 29 (total of 29 days) LINFORD 7-FEB-94 1-MAR-94 * 23 (total of 23 days) SLATER 1-FEB-94 * 3-FEB-94 3 (total of 3 days) LABONTE 1-FEB-94 * 1-MAR-94 * 29 (total of 29 days) CANFIELD 1-FEB-94 * 11-FEB-94 11 (total of 11 days) ---------------------------------------------------------------- Grand Total of 124 days for 6 people NOTE: The "*" signifies travel that actually ends after 1-MAR-94 -- Planned SXT travel for the month of March 1994: -- ACTON 1-MAR-94 * 31-MAR-94 * 31 (total of 31 days) HUDSON 1-MAR-94 * 31-MAR-94 * 31 (total of 31 days) LINFORD 1-MAR-94 * 9-MAR-94 9 (total of 9 days) SLATER 27-MAR-94 31-MAR-94 * 5 (total of 5 days) LABONTE 1-MAR-94 * 31-MAR-94 * 31 (total of 31 days) HARVEY 20-MAR-94 31-MAR-94 * 12 (total of 12 days) ---------------------------------------------------------------- Grand Total of 119 days for 6 people NOTE: The "*" signifies travel that actually ends after 31-MAR-94 K. Strong will be travelling to GSFC for the SPARTAN workshop on 14-March. Respectfully submitted, Keith Strong Frank Friedlaender Page 12 MONTANA STATE UNIVERSITY MSU ACTIVITY REPORT FOR JANUARY-FEBRUARY 1994 --------------------------------------------- MAJOR ACTIVITIES =============== Routine activities at MSU include project management duties, with Handy maintaining our rapport with the computers and Alexander keeping tabs on the budget. Acton has been on Yohkoh operational duty as Chief Observer at ISAS since Feb1 and will remain in Japan until May 1. Alexander is teaching a graduate level Solar Astrophysics course and this will continue until the end of March. Acton prepared cleaned-up SXT composite full-frame images for two different days in April 1993 in support of the analysis of the SPARTAN 1 data by Lika Guhathukurta and collaborators. SXT images were prepared and sent off to Jay Pasachof for use in a future book and to Science magazine for use in illustrating an article by Jim Glanz on coronal heating. Good news for February was that Handy was awarded a Solar Physics studentship by the Solar Physics Division of the AAS. The award of $800 will be used to finance Handy's attendance at the AGU meeting in Baltimore this May. The group here at MSU have submitted 3 abstracts for this meeting. Handy will also be attending a meeting at John Hopkins University in Baltimore on "Analysis of Emission Lines" immediately prior to the AGU. This will be supplemented by a visit to GSFC. Alexander submitted an abstract to the 30th COSPAR Scientific Assembly (Session E2.2 - Solar flare, coronal and heliospheric dynamics). On the research front, Handy has started analyzing the large scale loop region to the east of AR7260 as per our TBB item. This will provide the basis for the AGU presentation. Alexander has been looking at loop scaling models and the various energy loss mechanisms to assist in this research. In conjunction with Sarah Matthews at the University of Glasgow, Alexander has just completed a paper entitled "Particle Acceleration and the Decay of Soft X-ray Non-thermal Line Broadening in Solar Flares" and this is expected to be submitted in the next few days. Alexander also carried out some work with Valentina Zharkova on the effects of a converging geometry on the heating function in solar flares. This work is ongoing. While at ISAS Acton is working on characterizing the radiative energy losses of different types of coronal structures, segregated on the basis of brightness. This work is being done in collaboration with Hiroshi Hara. February also saw the completion of our NATO Collaborative Research Proposal entitled "The Role of Magnetic Loops in Heating the Solar Corona". This proposal is in conjunction with Mullard Space Science Lab and the University of St. Andrews with Alexander as Project Coordinator and Culhane and Hood as Principal Investigators. Handy got our two PC's running Unix (FreeBSD) and X-windows for easy access to SXT4 and now SXT4 has been upgraded to Ultrix 4.3a and we have IDL 3.5 installed and running. In addition, he installed our new Tektronix IIsd colour printer and has our video system singing and dancing. The MSU SXT platter was fairly active in the last couple of months, travelling almost as much as Loren Acton. Our laser-disk player and platter was loaned out for a successful performance at the IACG meeting in Easton, Maryland and was again sent East for use for a congressional briefing by Wes Huntress which was called off because of the weather. Page 13 The MSU team will be joined by another graduate student this summer. Mark Weber (a grad student here at MSU) will be working with us over the summer and should be the recipient of a Montana Space Grant Fellowship which will fund him to work with us over the next year or so. Miscellaneous activities include an MSU Physics Colloquium, " Explosions on the Sun: the enigma of solar flares" by Alexander, an astrophysics/relativity seminar presentation by Alexander entitled "How bald is the Universe?", a talk on "Science in Space" at Bozeman's Morningstar School by Acton who was impressed by the alert interest in science by the students in this top-notch grade school (material was also provided for 2 other schools in Montana). The plot_trav procedure of Morrison was modified by Alexander to work for MSU personnel. Once the problems with the paths have been sorted this may be called using MSU_trav. PLANS for MARCH-APRIL ==================== Alexander to head off to ISAS for 2 months operations duty starting April 2. Handy to prepare PhD oral on Plasma Diagnostics. Handy to continue analysis of large scale loops in preparation for AGU. Acton to present talk at Museum of Rockies as part of their Pioneering Space exhibit. Acton to remain as Chief Observer at ISAS until May 1. Alexander to work on loop geometry for use with SXT and to study the heating and subsequent cooling of large scale loop structures. Alexander to present research graduate lecture on Solar Physics to encourage interest in Solar group at MSU. New student to apply for Space Grant Fellowship. Completion of Solar Astro course. Page 14 YOHKOH / SXT ACTIVITY REPORT STANFORD TEAM January / February 1994 We have made progress in a number of YOHKOH-related areas over the past two months. Jim Klimchuk and graduate student Lisa Porter completed their measurements of coronal loop parameters (pressure, temperature, density, width, and length), including careful estimates of random and systematic errors, and have found an inverse correlation between the pressures and lengths of forty-six loops. This has important implications for theories of coronal heating. They also found that the intensity and pressure time scales of the loops are generally many times larger than the radiative and conductive cooling times, implying that the loops are quasi-steadily heated. In related work, Klimchuk collaborated with John Raymond of the Center for Astrophysics to generate a radiative loss function appropriate to the range of temperatures commonly observed in non- flaring loops. This function makes use of the best estimates of elemental abundances in the corona (modified Meyer values). Also during this period, Klimchuk worked on a draft of a paper describing his collaboration with Dale Gary of Caltech. A comparison of temperatures and emission measures observed in microwaves and soft X-rays indicates that temperature decreases with height above the base of the corona in active regions. This result has implications for coronal heating and is consistent with the results that Klimchuk and Porter obtained for individual coronal loops. Graduate student Slava Glukhov developed an IDL routine for image deconvolution and noise reduction that is based on the maximum entropy method. He tested this routine with both an ideal synthetic image and a real YOHKOH image and found that the noise reduction and spatial resolution improvement are substantial. George Roumeliotis continued to develop and test his vector magnetic field extrapolation routine and has recently concentrated on the reconciliation of the 180-degree ambiguity in the transverse field component. He has now obtained realistic extrapolations from both synthetic and real vector magnetograms. Peter Sturrock began to study the Hall effect and the possibility that coronal electric currents are "shorted out" in the much more resistive temperature minimum region. This has important consequences for both the heating of the chromosphere and the existence of current sheets in the corona (or the lack thereof). This period also saw the culmination of Porter, Klimchuk, and Sturrock's long-term study of the dissipation of fast and slow mode MHD waves by compressive viscosity and thermal conduction. Two papers were submitted to the Astrophysical Journal entitled "The Possible Role of MHD Waves in Heating the Solar Corona" and "The Possible Role of High-Frequency Waves in Heating Solar Coronal Loops." Over the next two months, we will continue to work in all of these unfinished areas. We will also prepare for the upcoming SPD / AGU meeting in Baltimore, at which Sturrock, Klimchuk, Roumeliotis, Bai, and Porter all plan to present results. In addition, Klimchuk hopes to visit ISAS during this period. Page 15 YOHKOH / SXT ACTIVITY REPORT SOLAR PHYSICS RESEARCH CORPORATION January / February 1994 Karen L. Harvey Activity the last two months are as follows: 1. Continued work on the collaborative observing program between SXT/Yohkoh and the NSO/KP magnetograph of XBPs on 9-10 December 1993, 17-21 May 1993, and the most recent successful collaboration during 28 November-3 December 1993. 2. Continued the multi-observatory collaborative observing program to study X-ray bright points. A collaboration that was to begin on 19 January 1994, was canceled due to increased levels of solar activity. Beginning on 8 March 1994, the overlap between the observing window at NSO/KP, BBSO, and MSO will once again coincide with the direct communications between Yohkoh and Japan. I have requested another XBP collaboration. One objective of this run, depending on conditions, is to see just how faint XBPs are. If this objective is not possible, we will continue with the highest-possible time-resolution X-ray observations. 3. Began study of evolution of the magnetic field structures underlying X-ray jets. This is being done in collaboration with K. Shibata, who provided a list of X-ray jets he found from 1 November 1991 to 30 April 1992. This list was recently updated by Mr. Shimojo, a student at Tokai University. Two events have been studied extensively, those on 12 November 1991 and 7 December 1991. Both events occur at sites where magnetic flux is canceling; the canceling bipoles resulted from magnetic flux that emerged earlier, which then encountered adjacent opposite-polarity network. 4. In collaboration with G. Poletto and S. Suess, began assessing SXT images during selected intervals during 1993 for XBP counts within a lobe of the polar coronal hole at the South Pole . The high-speed stream originating in this coronal hole has been observed on several successive solar rotations. The objective of this study is to determine if XBPs (used as a `proxy' for polar plumes) occur in sufficient numbers to account for the mass flux in coronal holes. A report of the progress of the work will be presented by G. Poletto at a SOHO meeting in September. 5. Continued updating of bibliography of Yohkoh papers; the bibliography is being restructured for easier access as per conversation with N. Nitta and K. Strong. A list of papers in refereed journals and meeting proceedings separated by was compiled, and is now available on the Lockheed and ISAS computers. 6. Prepared an abstract for the joint AGU/SPD meeting in May 1994 on 'X-Ray Bright Points: The Signature of Magnetic Field Reconnection'. Page 16 UNIVERSITY OF HAWAII ACTIVITY REPORT (R. CANFIELD) MAJOR ACTIVITIES FOR THE MONTHS OF JANUARY AND FEBRUARY Our most important activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition at Mees, instrument development and maintenance at Mees, analysis of Yohkoh/Mees data, manuscript and talks about research results, and participation in meetings. Operational support for SXT was provided by Hudson, Canfield, and LaBonte at ISAS (SSOC Toban), Judd, Nitta, and Douglass at Mees (observatory operations), and Jiao, Leka, Metcalf, and Wuelser in Manoa (Mees Yohkoh Duty Scientist). Mees was closed the week of 14 February for maintenance on the IVM and Stokes Polarimeter and the development of a full-sun rastering capability for the MCCD. Solar activity was low. Metcalf recomputed the offset between the SXT NaBan and X-Ray filters for Kosugi. This entailed a rewrite of the SXT_CENTER program which is now consistent with FIND_LIMB for NaBan images. The results indicate that his original computation of the offset was correct. He worked with Jiao to address several problems in their study of the height dependence of the chromospheric magnetic field using a combination of Na-D and FeI vector magnetograms. This paper is now in the hands of co-authors for comments. He completed a movie on inter-region connections involving AR7260 for Acton. He analyzed AR7414 Stokes vector magnetograms data for a study of the height dependence of chromospheric fields with Tom Moran (GSFC). He continued his analysis of the IVM H-alpha data from October, 1992. In particular, he is investigating methods for reducing the errors due to differential blurring of the raw IVM images. He applied the deconvolution algorithm of Pina and Puetter to SXT X-ray data with very encouraging results. This algorithm should be very useful for deconvolving the SXT point spread function from X-ray images. Leka spent January and the first half of February finishing the manuscript for the `roadmap' paper on AR7260 (her thesis work), and submitted it for publication. She traveled to the US mainland and gave invited talks on results from SXT and IVM observations of twisted emerging flux in AR7260, as listed below. Hudson attended the AAS meeting in Washington to present a poster on the Yohkoh observations of the transit of Mercury and the partial eclipse of November, 1993. During January and February his main scientific activities were (a) the preparation of software and some data work on intercom- parisons of SXT X-ray photometry with GOES and other references (mainly this project aims at trying to get some idea about dirt on the CCD); (b) the preparation of software for intercomparison of Yohkoh and Ulysses data Page17 during the S polar passage of Ulysses; (c) discovery in the 14 Feb 1992 event of a mm-wave impulsive spike, which could be a second Yohkoh event related to the remarkable impulse-response mm-wave events discovered by Stephen White (BIMA); (d) analysis of the 21 Feb 1992 flare, following up on the discovery of a rapidly rising ejection in the early phase full-frame images. The ejection has a limb-brightened, hollow brightness distribution, suggesting a hot skin around a cool prominence as it erupts. Wuelser and Bastian (NRAO) worked on the coordinated Mees, VLA, and Yohkoh observations of the flare on 20-Aug-92 17:20 UT. The data sets were co-registered with an accuracy of about 2 arcseconds. The physical interpretation of the combined data set is underway. Wuelser also continued to study the temporal evolution of chromospheric heating, chromospheric evaporation, and flare energetics in large flares. Wuelser and Waterson lead an effort to upgrade the Mees CCD imaging spectrograph (MCCD). The upgrade includes accurate position encoding and the ability to carry out large area scans (up to the full sun). This ability will be particularly important for coordinated observations during the Ulysses South Pole flyby. Jiao and Canfield finished the co-registration and measurements for their study of correlations between thickness variations along SXT coronal loops and magnetic fields B and electrical current densities Jz at their footpoints, done in collaboration with Klimchuk. Three regions were studied: AR7260, AR6919 and AR6952. In all three, they found a significant inverse correlation between loop thickness asymmetry and footpoint Jz asymmetry. They found a consistent, though statistically weaker, inverse correlation between loops thickness asymmetry and endpoint $B_t$ asymmetry. For the most flare-productive region (AR 6919), they found a significant relationship between loop apex expansion factor and average endpoint current density. In this region, the loops with larger endpoint Jz values showed no apex expansion, while those with low endpoint Jz values had apex expansion factors ranging from 1.0 to 1.9. These findings support the hypotheses that the coronal flux tubes studied are force-free and that currents play a role in confining their X-ray--emitting plasmas. Canfield spent 4 weeks in Japan, except for a few days attending the meeting of the Interagency Coordinating Group in Maryland to learn more about coordinated Ulysses, Yohkoh, and Mees observational requirements. During the time in Japan he worked with Shibata, Shimojo, Yokoyama, and Reardon X-ray jets (observed by SXT) and H-alpha surges (observed with the MCCD at Mees) in AR7260. This group identified eight events observed both in X-rays and H-alpha. Reardon developed the overlay software, and the study of the spatial and temporal relationships between X-ray and H-alpha emission and motion is underway. Canfield also gave talks at Kyoto and Mitata (below) and served at SSOC toban (replaced by Labonte during the IACG meeting). He worked with Petsov and Metcalf on patterns of helicity in active regions (the subject of the Mitaka talk) and Reardon on moving blueshift events prior to the eruption of the 15 Nov 1992 flare (the subject of the Kyoto talk). He represented the Hawaii group at the Yohkoh Page 17 mini-workshop on the August 1993 emerging flux campaign, in collaboration with Mickey and Metcalf. PLANS FOR MARCH AND APRIL Metcalf will address co-author comments and submit the paper with Jiao on the height dependence of chromospheric magnetic fields. He will provide magnetic field data to to George Roumeliotis (Stanford) to use in modeling of coronal fields for comparison with SXT images. He plans to implement a new idea for the resolution of the 180 degree ambiguity in vector magnetograph data involving only the absolute minimization of the divergence of the field. He plans to continue the analysis of the IVM H-alpha data. Leka will help complete the comparison between the IVM and the Stokes Polarimeter during March and April, and plans to submit a manuscript on the evidence for twisted emerging flux for publication by the end of this period. She will also prepare a presentation on a quantitative analysis of the currents and magnetic flux in emerging sunspot groups for the May 1994 AGU/SPD meeting. Hudson's main focus will remain on the Ulysses/Yohkoh comparisons. He will travel to JPL and Stanford to learn what he can about relevant data and theory, giving informal talks at JPL, Caltech, Berkeley, and Stanford. In the meanwhile, he plans to write up the 21 Feb 1994 event and complete the first phase of the SXT/GOES/BCS flux calibration exercise. He plans to finish the four-page Kofu paper on mm-wave events and loop-like white- light flares (co-authors Van Driel and Kosugi). He also will work with Kurokawa (Hida) on SXT data for a remarkable ejective flare, well-observed by Hida and Yohkoh, that looks like a clear case of flare driven reconnection. Wuelser will continue his study of chromospheric heating and flare energetics, and the analysis of the 20-Aug-92 flare with Bastian, as well as the upgrade of the Mees CCD imaging spectrograph (MCCD). Canfield will work on the analysis of the jets/surges data with Reardon and collaborators in Japan and on the manuscript about preflare filament eruption and tether cutting before the 1991 Nov 15 flare. ----------------------------------------------------------------------------- UNIVERSITY OF CALIFORNIA No input Received Page 19 ------------------------------------------------------------------------------- NASA REPORT DOCUMENTATION PAGE (IN LIEU OF NASA FORM 1626) --------------------|--------------------------|------------------------------- 1. REPORT NO. | 2. GOVERNMENT | 3. RECIPIENT'S DR-01 | ACCESSION NO. | CATALOG NO. --------------------|--------------------------|------------------------------- 4. TITLE AND SUBTITLE | 5. REPORT DATE Monthly progress report - for the month of | 10 March 1994 February 1994 |------------------------------- | 6. PERFORMING ORG | CODE: O/91-30 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- K. T. Strong | TION REPORT NO: F. M. Friedlaender | |------------------------------- -----------------------------------------------|10. WORK UNIT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS | Lockheed Palo Alto Research Labs B/252 |------------------------------- Solar & Astrophysics Laboratory O/91-30 |11. CONTRACT OR GRANT NO. 3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 37334 -----------------------------------------------|------------------------------- 12. SPONSORING AGENCY NAME AND ADDRESS |13. TYPE OF REPORT AND Marshall Space Flight Center (Explorer Program)| PERIOD COVERED Huntsville Alabama 35812 | Progress report for the month | of February 1994 |------------------------------- |14. SPONSORING AGENCY | CODE MSFC / AP32 -----------------------------------------------|------------------------------- 15. SUPPLEMENTARY NOTES ------------------------------------------------------------------------------- 16. ABSTRACT The SOLAR-A Mission is a program of the Institute of Space and Astronautical Science (ISAS), the Japanese agency for scientific space activity. The SOLAR-A satellite was launched on August 30, 1991 to study high energy phenomena in solar flares. As an international cooperative agreement, Lockheed, under NASA contract, is providing a scientific investigation and has prepared the Soft X-ray Telescope (SXT), one of the two primary experiments of the mission. --------------------------------------|---------------------------------------- 17. KEY WORDS (SUGGESTED BY | 18. DISTRIBUTION STATEMENT AUTHOR(S)) Solar-A, X-ray, CCD, | Space Science, Solar Physics ------------------------|-------------|----------|-----------------|----------- 19. SECURITY CLASSIF. | 20. SECURITY CLASSIF. | 21. NO OF PAGES |22. PRICE (OF THIS REPORT) | (OF THIS PAGE) | | None | None | 19 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-0001