Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for August 1994) OVERVIEW 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 30 August 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 We celebrated three years of operations that have yielded some extremely interesting data on a wide range of solar phenomena. We have also submitted a proposal to MSFC for the operations of SXT on the Yohkoh mission for a fourth year. The current level of funding and the broad participation of our Co-I's have allowed us to be participants in an extremely productive endeavor. << Solar Activity >> Solar activity remained at a moderate level in August. There were eight major flares during the month. NOAA Active Size Date and Time Region Number (GOES Class) (UT) AR 7765 M3.9 1994 August 14 17:38 AR 7765 M1.2 1994 August 15 12:51 AR 7765 M1.5 1994 August 17 01:11 AR 7765 M1.1 1994 August 18 03:05 AR 7765 M1.6 1994 August 19 02:58 AR 7773 M1.1 1994 August 30 08:30 AR 7773 M1.4 1994 August 30 10:45 Most of them came from a rapidly growing active region, NOAA AR 7765, which first appeared as an inconspicuous X-ray bright point on 11 August and rapidly grew in the next 24 hours. Over the next 6 days it produced a string Page 2 of small (C) flares along with six M flares. Active region 7765 was not only one to undergo major change during the month. AR 7766 also grew rapidly but interestingly produced no significant flaring. There was a large-scale eruption on the east limb on 24 August which occurred as AR 7770 appeared nearby, although this may have been a coincidence. The new region (AR 7773) that appeared on the east limb of the Sun on 29 August and produced two M flares in quick succession on 30 August. According to the NOAA solar forecasters, this region seems to be a new area of spot emergence and may be a source of more major flares in the coming weeks. << Campaigns >> A campaign organized by Hida Observatory to characterize emerging flux was successfully supported at the beginning of the month. We continue the regular weekly off point with deep X-ray exposures to support the Ulysses southern polar passage. We have been holding some preliminary discussion amongst ourselves and with the SPARTAN teams in preparation for the Shuttle flight of SPARTAN early next month. The SXT observing modes will involve taking deeper soft X-ray images of the southern polar region, which is where the SPARTAN coronagraphs will likely point, in support of Ulysses which is nearing its southern polar passage. << Science >> We have been making significant progress in accumulating different types of quiet Sun data and analyzing the results of the various campaigns which we have been conducting on X-ray bright points, emerging flux regions, filaments, and coronal hole evolution. Much of the month was spent revising (and in some case writing!) our COSPAR papers. Preparations are also being made for the next science meeting in Hawaii. We have had some lively (email) debates with Jack Gosling about his "flare myth" paper. Hugh Hudson, Bernie Haisch and Keith Strong have drafted a response to it and submitted it to JGR but obviously the controversy will continue. The SXT team has had a large number of inquiries, visits, and sample-data requests during this month, probably as a result of the NASA Guest Scientist Program. Proposals are due by the middle of next month so many researchers are wanting guidance as what they can and cannot do. Our Page 3 policy not to be involved in the proposals as PIs or CoIs and hence not to appear to endorse one proposal over any other proposal has drawn very positive responses from several of the potential proposers. << Papers and Conferences >> - Papers Published (1) - "Asymptotic forms for the energy of force-free field configurations of translational symmetry", P. A. Sturrock, S. K. Antiochos, J. A. Klimchuk, and G. Roumeliotis, Ap.J., vol. 431, p. 870 (August 20, 1994) - Papers accepted (4) - "Nonthermal soft X-ray line broadening in gamma ray flares" D. Alexander, Adv. Space Res., 1994 "The Magnetic Evolution of the Activity Complex AR7260: A Roadmap" K. D. Leka, L. van Driel-Gesztelyi, N. Nitta, R. C. Canfield, D. L. Mickey, T. Sakurai, K. Ichimoto, Solar Phys. "Is the Solar Chromospheric Magnetic Field Force-Free?", Thomas R. Metcalf, Litao Jiao, Han Uitenbroek, Alexander N. McClymont, and Richard C. Canfield, Astrophys. J. "Resolving the 180 Degree Ambiguity in Vector Magnetic Field Measurements: The 'Minimum' Energy Solution", Thomas R. Metcalf, Solar Phys. - Papers submitted (1) - "Comment on 'The Solar Flare Myth'", Hudson, H.S., Strong, K.T., and Haisch, B.M., JGR - Presentations (3) - "A Space-Based Vector Magnetograph: Opportunities and Tradeoffs", R. C. Canfield, in "International Solar-B Meeting", ISAS, 5-8 July, 1994. "X-Ray Jets and H-alpha Surges in AR 7260", R.C. Canfield, K.P. Reardon, K.D. Leka, K. Shibata, M. Shimojo, T. Yokoyama, in "Currents Trends in Solar and Astrophysical Magnetohydrodynamics", Boulder, 2-5 August 1994. "Resolving the 180 Degree Ambiguity in Vector Magnetograms: The 'Minimum' Energy Solution", Thomas R. Metcalf, Solar Neighborhood Meeting, Big Bear Solar Observatory, August 12, 1994. Page 4 - Abstracts (0) - << Public Use of SXT Images >> Gary Linford and Keith Strong prepared another in the series of the monthly articles for Sky & Telescope, this time incorporating GOES data with four SXT images taken about a week apart to cover the X-ray Sun for the whole month. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function well with a normal level of Single Event Upsets (SEUs). No significant degradation in the instrument has occurred since the loss of the front thermal shield in 1992. The overlap between Yohkoh and ASCA data passes is slowly getting worse but Yohkoh is only loosing a few passes at the moment. The SEU problems suffered by SXT in August 1994 are as follows: Bit Map Error: 940819-0824 ( 1st pass, 20 Aug 94) Bit Map Error: 940824-0721 (Pass 1 on 24-Aug-94) Last month the Engineering Summary Table showed a large increase in CCD dark current for the month of July. Despite the value in the table, there has NOT been any substantial increase in the CCD dark current. The value in table was caused by a dark table sequence that was run in July that erroneously included a diffuser image. This caused the CCD to be flooded with so much light that the following dark image was not adequately flushed. Therefore, some dark images had a large signal that was left over from the previous image. These images were included automatically in the SXT dark current database and in the summary table that was prepared for the monthly report. The SXT sequence table has been corrected, so this situation should not reoccur, but if it does the engineering software is now improved to detect this situation will not include incorrect dark current images. The error in the sequence table was not harmful to the CCD in any way and the only effect was to make some dark images unusable. One other point to note is that the statistics that are reported for the most recent month are never complete at the time of preparation, since the most recent data from all the DSN locations have not been reformatted. Thus, the August data reported here are not complete, but will be fully reported next month. Page 5 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot ------------------------------------------------------------------------------ Thru May-92 45673 23593 137658 77530 215188 81187 26.59 Jun-92 7230 2819 24375 13361 37736 11419 23.23 Jul-92 6535 3085 24622 11481 36103 13065 26.57 Aug-92 6572 2978 24207 11154 35361 13550 27.70 Sep-92 6087 2916 26832 20042 46874 15729 25.12 Oct-92 6753 2552 51037 14709 65746 23529 26.36 Nov-92 6648 2949 24345 14832 39177 12859 24.71 Dec-92 6766 3008 24188 6600 30788 12454 28.80 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 8504 3864 42953 5849 48802 23896 32.87 Dec-93 5898 3047 21128 13297 34425 13001 27.41 Jan-94 6934 2804 28567 10960 39527 13746 25.80 Feb-94 7000 2840 23021 5819 28840 11257 28.07 Mar-94 7736 2627 69273 3733 73006 31464 30.12 Apr-94 6142 2741 22707 3390 26097 12338 32.10 May-94 7070 2679 25260 3040 28300 10862 27.74 Jun-94 7417 2738 36795 1996 38791 15760 28.89 Jul-94 7488 2941 50540 3275 53815 24153 30.98 Aug-94 3164 1051 19282 300 19582 7570 27.88 Total 234416 105074 1026460 314387 1340847 527109 28.22 ------------------------------------------------------------------------------ Number of Full Frame Images Received: 234416 Number of Observing Region Images Received: 1340847 Total: 1575263 Approximate Number of Shutter Moves/CCD Readouts: 2738931 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 6 << 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 (%) 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 45.33 555.8 32047 3210 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 46.03 582.1 40449 3246 19.3 N/A Mar-94 45.92 578.0 39715 3420 18.2 N/A Apr-94 45.97 579.9 41302 3721 25.2 / 3 17.8 N/A May-94 46.25 590.3 45476 3557 18.3 N/A Jun-94 45.83 574.6 39340 3547 17.8 N/A Jul-94 46.76 609.5 53417 3990 18.2 N/A Aug-94 47.05 620.5 59019 4346 25.2 / 3 17.4 N/A NOTES: * The dark current calculations are using full half resolution 2.668 sec 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 readout noise and is not a function of exposure duration. Page 7 << Personnel Travel >> SXT Foreign Travel between 1-AUG-94 and 31-AUG-94 BRUNER 20-AUG-94 31-AUG-94 * 12 (total of 12 days) HUDSON 1-AUG-94 * 31-AUG-94 * 31 (total of 31 days) LINFORD 1-AUG-94 * 25-AUG-94 25 (total of 25 days) NITTA 1-AUG-94 * 26-AUG-94 26 (total of 26 days) WUELSER 30-AUG-94 31-AUG-94 * 2 (total of 2 days) ---------------------------------------------------------------- Grand Total of 96 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-AUG-94 Planned SXT Foreign Travel between 1-SEP-94 and 30-SEP-94 BRUNER 1-SEP-94 * 20-SEP-94 20 (total of 20 days) FREELAND 7-SEP-94 30-SEP-94 * 24 (total of 24 days) HUDSON 1-SEP-94 * 16-SEP-94 16 26-SEP-94 30-SEP-94 * 5 (total of 21 days) LEMEN 26-SEP-94 30-SEP-94 * 5 (total of 5 days) WUELSER 1-SEP-94 * 26-SEP-94 26 (total of 26 days) ---------------------------------------------------------------- Grand Total of 96 days for 5 people NOTE: The "*" signifies travel that actually ends after 30-SEP-94 Respectfully submitted, Keith T. Strong Frank Friedlaender Page 8 YOHKOH/SXT CONTRACT REPORT MONTANA STATE UNIVERSITY for July - August 1994 Because of travel, vacations, and service at ISAS most of the interaction of the MSU team has been by e-mail for the past two months. Here are some highlights of the period. Acton spent July and early August working on a coronal heating paper to be co-authored with Sturrock and Klimchuk for Annual Reviews of Astronomy and Astrophysics. He is increasingly convinced that most coronal heating is from flare-like process(es) with wave heating playing a secondary and minor role, if any at all. He has also prepared x-ray irradiance data for a collaboration with White at HAO to publish this for use by aeronomists. Along the same lines, he provided some 1992 irradiance data to Kumar at Howard University for modeling production of NO and comparison with ATMOS results from the ATLAS-1 mission. During a visit to Moscow on 19 August Acton gave a well-attended colloquium on Yohkoh results at the Lebedev Institute and spent the afternoon going over results from Coronas-1. Zhitnik's data are really very good and will be very interesting to compare with SXT because of the lower temperature range covered. Their instrument is calibrated (piecewise) and innovative, but the satellite and telemetry systems are marginal. The appearance of their data at meetings suffers from the present limitation of a 4 bit color capability on their printer. Alexander spent a week at the University of Glasgow prior to attending the COSPAR Assembly in Hamburg, Germany, where he was the referee for one of the COSPAR sessions. His paper, "Nonthermal soft X-ray line broadening in gamma ray flares" has been accepted for publication in Advances in Space Research. His NATO Collaborative Research Grant was funded to the tune of 306,000 Belgian Francs. The proposal, "The role of magnetic loops in heating the solar corona" provides travel funds for a collaborative project between MSU, MSSL and the University of St. Andrews. His present work includes study of the 14 April 1994 Polar Page 9 Crown event in preparation for next month's SoHO Workshop in Estes Park, CO, with Slater, Hudson, Harvey and McAllister. In spring semester Alexander will teach a graduate astrophysics course entitled "The Physics of Astrophysics" at MSU. Handy spent July as SXT Chief Observer at ISAS where he worked on x-ray scattering and dark frame calibration issues. Returning to MSU he continues service as the systems manager of the solar group and reports that the university will soon upgrade to a T1 (1 Mb/s) internet link. Priority for the next reporting period is to settle on a topic for his dissertation research. Weber has completed a suite of software for studying coronal differential rotation from the Yohkoh SFD database. The first report of this work will be at the SoHO workshop at Estes Park, CO, in September. Adina Ragenovich, a graduate student in computer science, has begun a Master's thesis on scientific visualization of solar processes through the use of the "particle systems" approach. This is the visualization system used by the likes of Spielberg for explosions, smoke, etc. During the next bimester Acton will attend the IACG meeting in Austria and the 3rd Coordinated Data Analysis Workshop in Hawaii. Alexander and Weber will attend the SoHO workshop following which Alexander will go to ISAS for Chief Observer service. Page 10 YOHKOH/SXT PROGRESS REPORT FROM UCB (2-SEP-1994) J McTiernan spent the last two weeks of July at ISAS, working on HXT images using the pixon method. A result of this work is now that the IDL deconvolution procedure for HXT images, HXT\_MULTIMG, contains the pixon option. It can also be run non-interactively, pixon images take much longer than images obtained using the Max. Entropy Method. Presently we are testing the pixon method on model two-footpoint sources, the insight gained here will be applied to continuing work on spatial dependence of HXT spectra. A rough draft of a report on SXT uncertainties has been finished, including a Mote Carlo analysis of the uncertainty in temperature and emission measure. A result of this work has been the addition of an extra factor in the emission measure uncertainty in the analysis program SXT\_TEEM2. Even with the correction, it seems that the emission measure uncertainty for the thin-thin filter ratio (AlMG/Al.1) is underestimated. We are presently comparing the measured uncertainties in emission measure with the fluctuations seen in actual data. A program to use the Monte Carlo method for uncertainties, MC\_UNC, is now on-line at ISAS. Page 11 UNIVERSITY OF HAWAII ACTIVITY REPORT (R. CANFIELD) MAJOR ACTIVITIES FOR THE MONTHS OF JULY AND AUGUST Our most important activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition at Mees (including the Hida/SXT AFS campaign). development of full-disk observing capabilities, analysis of Yohkoh/Mees data, organization of the Coordinated Data Analysis Workshop (CDAW), participation in meetings, preparation of manuscripts, and passing of exams. Operational support for SXT was provided by Hudson at ISAS, as SXT Chief Observer and SSOC toban, Judd, Nitta, and Douglass at Mees (observatory operations), and Canfield, Jiao, Leka, Metcalf, and Wuelser in Manoa (Mees Yohkoh Duty Scientist). Jiao passed his candidacy exam, and has officially begun his thesis on the computation of 3-dimensional models of coronal magnetic fields from Mees Stokes Polarimeter data and comparison of the results to SXT images. He wrote programs to combine two magnetograms based on the correlation of the optical images (or field contours) or correlations with a parent magnetograms. However, because of evolution of magnetograms with time, even the robust correlation routines failed; further work is required. He made a concise and effective IDL program on the 3-D display of the restored 3-D loops on the top of their projected image from different view angles. Leka finished revising the `Roadmap' paper on evidence for flux emergence in AR 7260, as per the second iteration with the referee. She and G. Cauzzi shared duties as Mees campaign coordinator for Prof. Kurokawa's Hida/SXT coordinated observing campaign on arch filament systems. She also helped test the the IVM's use as a longitudinal magnetograph (instead of a full vector magnetograph) for one of the recent filament campaigns with Yohkoh. Metcalf provided R. O'Neil (Stanford) magnetograms and linear force-free magnetic field extrapolations for AR6624 and AR6619, which were observed with the multispectral imagers aboard Prof. Walker's rocket flight. Metcalf discussed his pixon code with R. Puetter (UCSD) and began incorporating his suggestions into the code for getting the best possible spatial resolution and image fidelity from HXT data. Finally, Metcalf continued to work on IVM data on H-alpha polarization during flares for the October period for which there are many oc-observed Yohkoh/Mees flares. For those data for which no Yohkoh data were available, he began a comparison of the IVM data to Nobeyama radioheliograph data. Page 12 The Mees CCD imaging spectrograph (MCCD) has been routinely taking full disk observations with the now operational mosaic capability. Wuelser wrote software to automatically re-assemble the mosaic tiles with high accuracy. Wuelser continued to work on the August 20, 1992 flare, in collaboration with Bastian. The flare morphology and loop connectivity is rather complex but now fairly well established. At this point the work focuses on trying to understand the relative strength of the microwave and hard X-ray emission in the various footpoint sources. Wuelser participated in an effort by Kosugi and Nishio to more precisely determine the roll angle of SXT. The opportunity for improved measurements came up as Yohkoh observed the transit of Mercury across the sun on Nov. 6, 1993. Hudson submitted a comment to J.G.R. on Gosling's "Solar Flare Myth" paper, with Keith Strong and Bernie Haisch as co-authors. The main purpose of this comment was to point out the strong parallels between CME-launching events, both inside and outside active regions, with what we normally call "flares". In the view of this comment, Gosling basically ignores the most interesting part of flare physics, namely the pre-post-flare-loop stages. It may well be that there are fundamental differences in the physics of events that launch CMEs, but there is no evidence for it yet, nor is there any compelling theoretical insight. In support of this effort, Hudson also worked up some material on high-latitude filament events in preparation for the October CDAW meeting. As a part of this, he attempted to measure temperatures for these huge, diffuse SXT structures. They are hot but not very hot, and the data analysis may not be able to go much deeper than this statement in some cases. In collaboration with M. Kundu (plus N. Nitta and J.-P. Raulin), Hudson worked with comparisons of Nancay meter-wave data and SXT images. This a subject near and dear to Hudson's heart, since the meter-wave data clearly show non-thermal particles of many kinds in many coronal situations; other people including J.-P. Wuelser and N. Gopalswamy are also now making efforts in these directions. Success here means that SXT can define the geometry and physical conditions in the radio sources with Page 13 much less ambiguity than the radio data themselves. The box score thus far is four successful matches between fast-drift bursts (one U event discovered by Pick et al.; see the Kofu conference proceedings) and three type III groups identified by the group led by Kundu. The type III bursts are clearly identifiable with "anemone jets" from the Shimojo-Shibata survey, or what had been called "squirters" by Acton and Morrison when they first spotted on the SXT movie. Hudson also continued his study of the early phases of the celebrated 21 Feb. 1992 event. What had been fairly obvious from the movie has now been quantitatively confirmed: there is an evacuation of the corona preceding the flare onset. This is consistent with the depletion of coronal material seen during a coronal mass ejection, but the soft X-ray observations (this appears to be the first case of this effect) show a much larger reduction than one typically sees in white light (a factor of two), implying that the mass ejection in this case at least consisted of hot material visible to SXT. Finally Hudson and Jim Ryan (U. New Hampshire) began in a serious manner the preparation of a review "Energetic Particles in Solar Flares" for Annual Reviews of Astronomy and Astrophysics. This is due in mid-October. Canfield worked with K. Shibata on the organization of the CDAW on Eruptive Phenomena in the Solar Corona. The dates of the workshop were changed to October 17-20, to eliminate conflict with a meeting at Nobeyama Radio Observatory. He and K. Reardon worked with K. Shibata, T. Yokoyama, and M. Shimojo on surges and jets in AR7260, including a productive session at the meeting on Solar and Astrophysical MHD in Boulder in August. The latest discovery in this productive collaboration is that the small flare-like brightenings associated with these surges and jets show that the flare ribbons approach one another, rather than moving apart, as they do in classic eruptive flares. This implies that during these events the reconnection moves progressively deeper into the small bipole as it reconnects with the overlying coronal field. This discovery also implies that the same footpoint approaching motion should take place in the "anemone" events associated with bright point flares in coronal holes. Page 14 PLANS FOR SEPTEMBER AND OCTOBER Jiao will work on 3-D restoration of solar coronal loops based on SXT soft X-ray images and will travel to San Diego to work with Z. Mikic to learn about his code for computation of 3-D coronal magnetic fields from photospheric vector magnetograms. Leka will finish and submit the paper on morphological and quantitative evidence that the flux emerging in the well-observed AR 7260 (the subject of her thesis) does so in twisted form, and carries current that emerges as the magnetic flux emerges. She will then prepare for her thesis defense. Metcalf will continue the analysis of the IVM H-alpha polarization data. He will work on a new version of the HXT pixon code, incorporating suggestions from R. Puetter. He will continue to work with G. Roumeliotis on the extrapolation of photospheric magnetic fields into the corona. Wuelser is staying at ISAS throughout September. He will continue his work with Bastian on the August 20, 1992 flare. In preparation of the upcoming CDAW workshop on Eruptive Phenomena, he plans to do a preliminary analysis of several flares associated with radio type II bursts. Hudson will support Yohkoh operations, work on the Annual Reviews article discussed above, and prepare for the CDAW. He would like to write up the Feb. 21 material, which appears to be a big discovery. This event also had one of the best-observed compact ejections, a hollow blob configuration with a stalk leading back to the flare cusp, so it presents the reconnection dilemma in extremely sharp form: on the one hand, the cusp and blob geometry looks exactly as it should for a classical reconnection model; on the other hand there is only outflow seen during the energy-release phase, whereas the reconnection models really require inflow. Canfield will work on the H-alpha surges and X-ray jets paper and organize and run the October Hawaii CDAW on eruptive phenomena. Page 15 Yohkoh/SXT Activity Report Stanford Team July/August 1994 During the past two months, Roumeliotis has drafted a paper describing his work on the simultaneous deconvolution and resampling of SXT images using a modified maximum likelihood approach. The method yields sharp images on a finer grid than the raw SXT images, and should be helpful in classification and morphological studies of soft X-ray loops. Sturrock and graduate student Slava Glukhov have been developing a numerical model to investigate the effects of the Hall electric current on the reconnection of coronal magnetic field lines. A new graduate student, Frankie Liu, has joined our group. Liu is currently working on a method for resolving the 180 degree ambiguity in vector magnetograph measurements of the transverse field at the photosphere. The method is interactive, with the user determining the orientation of the field lines at locations adjacent to the magnetic neutral lines - where the direction of the transverse field is generally well-determined from the requirement that the magnetic field should arch from the positive polarity to the negative polarity. Then the method of simulated annealing is used to determine the smoothest transverse field that is consistent with the orientations selected by the user. This method will be very useful in conjunction with the work of Roumeliotis on reconstructing the coronal magnetic field from vector magnetograph data. Page 16 Solar Physics Research Corporation Activity Report Karen L. Harvey Activity the last two months are as follows: (1) Because of the monsoon season in Arizona typical of our July and August weather, no XBP campaign was requested nor scheduled during this interval. A request for an XBP collaboration will be made for late September, pending solar activity and the timing of the SPARTAN launch and observations. The objective of this run will be to continue the variations and the association of He I 10830 dark points and X-ray bright points. The previous two runs were marginally successful in obtaining sufficient observations to accomplish this goal, hence our request to continue this observing program. (2) Continued the reduction of observations obtained in collaboration by Yohkoh SXT, NSO/KP, BBSO, and MSO during several of the XBP campaigns. This involves registration and cleaning up of the SXT PFIs and registration and co-alignment of the simultaneous NSO/KP magnetograms and He I 10830 spectroheliograms of the target regions. (3) continued updating of bibliography of Yohkoh papers; the bibliography is being restructured for easier access as per conversations with N. Nitta and K. Strong. A list of papers in refereed journals and meeting proceedings separated by year was compiled, and is now available on the Lockheed and ISAS computers. (4) In early August, presented a talk at the High Altitude Observatory, Boulder, CO on the He I 10830 two-ribbon events that follow the eruption of filaments and filament channels. Discussed were the characteristics of these events, their association with CMEs, and with the large-scale X-ray arcades seen in the Yohkoh SXT full-frame images. (5) Working on the analysis of the 14 April 1994 arcade event with David Alexander, Hugh Hudson, and Alan McAllister. This work will be presented by David Alexander at the SOHO meeting in late September. Page 17 ------------------------------------------------------------------------------- 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 September 1994 August 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 August 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 | 17 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office