Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for October 1994) OVERVIEW The YOHKOH Mission is a program of the Japanese Institute of Space and Astronautical Science (ISAS) with collaboration by the U. S. National Aeronautics and Space Administration and the U. K. Science and Engineering Research Council. The YOHKOH satellite was launched on 30 August 1991 from Kagoshima Space Center (KSC) in Japan. The purpose of this mission is to study high energy phenomena in solar flares and the sun's corona. 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 at the Lockheed Palo Alto Research Laboratory 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 The amendment to support operations in Japan through FY95 has been negotiated and all operations were continued in a seamless manner. Frank Friedlaender had the opportunity to present two papers on the management of the SXT Program at The International Astronautical Federation Congress in Jerusalem. It is very rewarding to talk about a program where the synergism of NASA/HQ, NASA/MSFC, Lockheed, the PI, and our Japanese colleagues work in such a constructive manner to produce a program that can be viewed as model. Some additional excitement in the form of two major earthquakes complemented the usual activity here at ISAS. The first earthquake measured 8.2 on the Richter scale with an aftershock the following day of strength 7.3. These 'quakes occurred quite far out in the Pacific and most of the damage was confined to the island of Hokkaido and the northern part of Honshu. Members of the team in Japan at the time were shaken but not stirred. << Solar Activity >> Sun was moderately quiet this month although several small active regions have emerged since the last rotation. The month started out with no major regions on the solar disk and very low X-ray fluxes. The best example of emerging active regions was NOAA AR 7790. This region produced the only major flare of this month, peaking at 21:27 U.T. on Page 2 19 October. It was classified as an M3 intensity flare by GOES and was a long duration event as it lasted for over 12 hours. AR 7792 also underwent significant growth since the last rotation when there was a small unnumbered plage in the area where it appeared. It produced another LDE flare at 10:09 UT on 25 October 94 which lasted nearly 6 hours but its peak intensity was 10% of the other flare. << Campaigns >> This was a busy month for campaigns; Yohkoh supported/ planned five campaigns: 1. "Chromospheric Ejections and Coronal Loops" which was coordinated by Brigitte Schmieder and Lidia van Driel-Gesztelyi at Meudon for 25 September to 7 October. Even though the solar activity is low, many interesting features were seen in the SXT images. 2. Karen Harvey planned another "X-ray Bright Point Study" for the first week of the month. 3. Synoptic Coronal Observations organized by Bernard Jackson (UCSD) and Richard Altrock (NSO/Sac. Peak) to study the temperature structure of the quiet corona. The program was scheduled for 10-24 October 1994 and involved a huge worldwide network of ground-based observatories and spacecraft. Yohkoh performed a series of offpoints of about 4 arcmin to the east, west and south to take a series of deep exposures 4. The flight of the Multispectral Solar Telescope from White Sands was scheduled for 25 October 1994 but has now been delayed until 3 November due to technical problems. 5. The SXT team has been planning observations of the solar eclipse that will take place on 3 November << Science >> The month has been a good one for publications with the distribution of the proceedings of the Kofu Symposium - A New Look at the Sun. The meeting was organized by Prof. Enome and was an excellent forum for the exchange of views on various flare and quiet Sun issues as highlighted by data from the Nobeyama Radioheliograph and Yohkoh. The book of the proceedings reflects the diversity of work going on between the radio community and Yohkoh and show the promise of new discoveries as these data sets are exploited further. Preparations have been going on for the San Francisco meeting of the AGU where there is a special session on polar physics that features Ulysses, SPARTAN, Page 3 and Yohkoh data. << Papers and Conferences Proceedings>> The following list is not necessarily a complete listing of publications over the last month that include scientists that are supported by the NASA SXT contract. - Papers Published (29) - "Thermal Plasmas in the Solar Corona: the Yohkoh Soft X-Ray Observations," H. S. Hudson, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 1, 1994 "Observations of the Structure and Dynamics of Coronal Loops," K.T. Strong, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 53, 1994 "Microflaring at the Feet of Large Active Region Loops," J. Porter, R. T. Moore, G. Roumeliotis, T. Shimizu, S. Tsuneta, P. A. Sturrock, and L. W. Acton, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 65, 1994 "Observation of 17 GHz Radio Emission from X-Ray Bright Points," M. R. Kundu, K. Shibasaki, S. Enome, and N. Nitta, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 79, 1994 "Observations of Enhanced Coronal Heating in Sheared Magnetic Fields," R. T. Moore, J. Porter, G. Roumeliotis, S. Tsuneta, T. Shimizu, P. A. Sturrock, and L. W. Acton, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 89, 1994 "Hard and Soft X-Ray Observations of a Super-Hot Thermal Flare of 6 February 1992," T. Kosugi, T. Sakao, S. Masuda, H. Hara, T. Shimizu, and H. S. Hudson, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 127, 1994 "Temperature Analysis of the Post-Flare Loops of June 25-26, 1992," B. Anwar, E. Hiei, H. S. Hudson, L. W. Acton, J. R. Lemen, and T. R. Metcalf, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 137, 1994 "Flares on September 6, 1992," R. Kitai, H. Kurokawa, Y. Funakoshi, Y. Nakai, K. Shibata, K. Yaji, N. Nitta, Page 4 Yohkoh Team and NAOJ Flare Telescope Team, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 147, 1994 "OVRO and NRO Observations of the Solar Flare on 1993, June 3," D. Gary, S. Enome, and M. Bruner, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 165, 1994 "Morphology of the 10 Million Degree Plasma in the Solar Flares and the Failure of the Chromospheric Evaporation Model," J. F. Seely, U. Feldman, G. A. Doschek, K. T. Strong, L. W. Acton, Y. Uchida, and S. Tsuneta, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 177, 1994 "H-alpha and X-Ray Signatures of Chromospheric Heating Observed in Solar Flares," J.-P. Wuelser, R. C. Canfield, T. Sakao, S. Masuda. T. Kosugi, and S. Tsuneta, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 195, 1994 "Energy Transport During a Solar Flare: VLA Observations of the M1.9 Flare of 20 August 1992," T. S. Bastian, N. Nitta, A. L. Kiplinger, and G. A. Dulk, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 199, 1994 "Multiwavelength Observations of a Solar Flare," S. M. White, A. S. Silva, I. de Pater, R. P. Lin, D. E. Gary, H. S. Hudson, J. G. Doyle, M. J. Hagyard, and M. R. Kundu, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 203, 1994 "Evidence for Both Electron Acceleration and Direct Heating in Solar Flares," B. R. Dennis, G. D. Holman, H. S. Hudson, T. Kosugi, K. T. Strong, and D. Zarro, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 217, 1994 "Energetic Electrons and Magnetic Field Structures in the Corona," M. Pick, A. Raoult, G. Trottet, N. Vilmer, K. Strong, and A. Magalhaes, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 263, 1994 "A Morphological Study of Magnetic Shear Development in a Flare-Productive Region NOAA 7270," H. Kurokawa, Page 5 R. Kitai, G. Kawai, K. Shibata, K. Yaji, K. Ichimoto, N. Nitta, and H. Zhang, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 283, 1994 "Combined HRTS-8 Sounding Rocket Observations and Yohkoh Soft X-Ray Observations of NOAA Active Region 7260 at the Solar Limb," C. M. Korendyke, K. P. Dere, G. E. Brueckner, K. Waljeski, and J. R. Lemen, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 293, 1994 "Implications of Coronal Abundance Variations," J. L. R. Saba and K. T. Strong, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 305, 1994 "Determining Point Spread Function of Space Observations Using Bid Algorithm," M. Karovska and H. S. Hudson, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 327, 1994 "Metric Type III Bursts From Flaring X-Ray Bright Points," M. R. Kundu, K. T. Strong, M. Pick, K. T. Harvey, S. R. Kane, S. M. White, and H. S. Hudson, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 343, 1994 "Study of Active Region Magnetic Field Structures Using VLA Radio, Yohkoh X-Ray and Mees Optical Observations," N. Gopalswamy, E. J. Schmahl, M. R. Kundu, J. R. Lemen, K. T. Strong, R. C. Canfield, and J. de la Beaujardiere, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 347, 1994 "Evolution of an Active Region and Flare Productivity," M. R. Kundu, K. Shibasaki, S. Enome, N. Nitta, M. Bruner, T. Sakao, and T. Kosugi, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 353, 1994 "A Search for 'Black-Light Flares,'" L. v. Driel-Gesztelyi, H. S. Hudson, B. Anwar, and E. Hiei, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 375, 1994 "Flares in Active Region NOAA 7260 - Role of Emerging Flux," N. Nitta, L. v. Driel-Gesztelyi, K. D. Leka, D. L. Mickey, T. R. Metcalf, J.-P. Wulser, K. Page 6 Ichimoto, T. Sakurai, and K. Shibata, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 385, 1994 "Multispacecraft Observations and Thick-Target Electron Beam Models for the 15-November-1991 Flare," J. M. McTiernan, S. R. Kane, K. Hurley, J. G. Laros, E. E. Fenimore, R. W. Klebsadel, M. Sommer, and M. Yoshimori, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 389, 1994 "Long Duration Events in Magnetic Arcades and Large Loops," A. Fludra, J. Jakimiec, M. Tomczak, J. L. Culhane, and L. W. Acton, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 393, 1994 "Analysis of Three Yohkoh White-Light Flares," H. S. Hudson, L. v. Driel-Gesztelyi, and T. Kosugi, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 397, 1994 "Soft X-Ray Feature in Active Regions Associated with Meter Wavelength Solar Radio Emission," S. Watari, T. Isobe, and Yohkoh SXT Team, Proc. of Kofu Symposium - A New Look at the Sun, Eds., Enome and Hirayama, NRO Report No. 360, Page 417, 1994 - Papers accepted (0) - - Papers submitted (1) - "A Comparison of Active Region Temperatures and Emission Measures Observed in Soft X-Rays and Microwaves and Implications for Coronal Heating" by J. A. Klimchuk and D. E. Gary to Ap. J. - Presentations (1) - "Yohkoh Observations Relevant to Mass Ejection" J. Klimchuk, (invited) at the 3rd SOHO Workshop in Estes Park, Sept. 26-30 - Abstracts submitted(0) - << Public Use of SXT Images >> Gary Linford and Keith Strong prepared another in the Page 7 series of the monthly articles for Sky & Telescope. Gary Linford and Loren Acton have been working on preparing a Yohkoh SXT picture to display at the NSF. They are making a high-quality version of the 2nd Yohkoh poster which will be printed and mounted in Sunnyvale and sent to NSF. Frank Friedlaender presented two papers on the management aspects of the SXT Program considering both cost constraints and the international aspects of the program at the International Astronautical Federation Congress in Jerusalem during the week of October 10. Frank was also responsible for organizing and implementing the Public Outreach Program as part of his responsibility as chairman of a special task force on Public Outreach under the auspices of the Education Committee of the IAF << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function well with no Single Event Upsets (SEUs) although there were a couple of usual sort of SXT table upload problems. No significant degradation in the instrument has occurred since the loss of the front thermal shield in 1992. Page 8 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jun-92 52903 26412 162033 90891 252924 92606 26.25 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 7370 2337 35067 3993 39060 13485 25.66 Sep-94 5584 2104 19537 2264 21801 8764 28.67 Total 244206 108464 1061782 320344 1382126 541788 28.16 Number of Full Frame Images Received: 244206 Number of Observing Region Images Received: 1382126 Total: 1626332 Approximate Number of Shutter Moves/CCD Readouts: 2832806 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 9 << 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 (%) 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 47.02 619.0 58434 4121 25.2 / 3 18.2 N/A Sep-94 47.07 620.9 58580 4028 18.2 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 10 << Personnel Travel >> SXT Foreign Travel between 1-OCT-94 and 31-OCT-94 ALEXANDER 2-OCT-94 31-OCT-94 * 30 (total of 30 days) FREELAND 1-OCT-94 * 7-OCT-94 7 (total of 7 days) HUDSON 1-OCT-94 * 14-OCT-94 14 24-OCT-94 31-OCT-94 * 8 (total of 22 days) LEMEN 1-OCT-94 * 31-OCT-94 31 (total of 31 days) LINFORD 18-OCT-94 31-OCT-94 * 14 (total of 14 days) NITTA 23-OCT-94 31-OCT-94 * 9 (total of 9 days) ---------------------------------------------------------------- Grand Total of 113 days for 6 people NOTE: The "*" signifies travel that actually ends after 31-OCT-94 SXT Foreign Travel between 1-NOV-94 and 30-NOV-94 ACTON 27-NOV-94 30-NOV-94 * 4 (total of 4 days) ALEXANDER 1-NOV-94 * 5-NOV-94 5 (total of 5 days) BRUNER 1-NOV-94 30-NOV-94 * 30 (total of 30 days) FREELAND 22-NOV-94 30-NOV-94 * 9 (total of 9 days) HANDY 5-NOV-94 30-NOV-94 * 26 (total of 26 days) HUDSON 1-NOV-94 * 30-NOV-94 * 30 (total of 30 days) LINFORD 1-NOV-94 * 17-NOV-94 17 (total of 17 days) NITTA 1-NOV-94 * 14-NOV-94 14 (total of 14 days) LEKA 7-NOV-94 30-NOV-94 * 24 (total of 24 days) ---------------------------------------------------------------- Grand Total of 159 days for 9 people NOTE: The "*" signifies travel that actually ends after 30-NOV-94 Respectfully submitted, Keith T. Strong Frank Friedlaender Page 11 YOHKOH/SXT CONTRACT REPORT MONTANA STATE UNIVERSITY September - October 1994 It has been a busy and productive bimester for the MSU group including participation in the SoHO workshop and the third Coordinated Data Analysis workshop at the University of Hawaii as well as Chief Observer duty at ISAS in Japan. Detailed plans were prepared for adding the recently approved TRACE mission to SXT as a major activity here. Highlights for the members of the MSU team follow. Acton, Klimchuk and Sturrock agreed to abandon their attempt to prepare a review paper on coronal heating for Annual Reviews. The paper kept turning itself into a research paper so that is now what will be written instead of the review. Acton spent time formalizing MSU plans to participate in the TRACE (Transition Region and Coronal Explorer) mission, realizing a dream of getting graduate students involved in the preparation of space instrumentation. He also attended the IACG (Inter-Agency Consultative Group) meeting in Krumbach, Austria to coordinate scientific programs with the four space agencies at a high level. This group has been responsible in the past year for two campaigns that will involve Yohkoh and Ulysses. Acton then spent a week in Hawaii at the 3rd CDAW (Coordinated Data Analysis Workshop) where he worked with Terry Forbes (of the University of New Hampshire) on flares with cusped x-ray loops. Alexander completed his presentation for the SoHO workshop, entitled "The Polar Crown Event of April 14 1994", in collaboration with Greg Slater, Hugh Hudson, Alan McAllister and Karen Harvey, to be published in the conference proceedings. This paper describes the event as observed by the Yohkoh SXT and several ground-based telescopes. Alexander also assisted Mark Weber of MSU in a paper on differential coronal rotation. Alexander has been in hot pursuit of international projects on a number of fronts, including some initial efforts on the NATO Collaborative Research Grant, discussions with Helen Mason of Cambridge regarding Yohkoh/SoHO collaborations, and also some preliminary discussions with McAllister (HAO) and Loretta Weiss (LANL) on future work on solar eruptive events and the connection between X-ray features in the solar atmosphere and observations in the interplanetary medium. Handy made a sudden and abrupt change in direction with the approval of the TRACE mission. Handy do his Ph.D. thesis on the preparation and calibration of the UV channel of the TRACE telescope with complementary theoretical analysis and interpretation of UV rocket data from Marilyn Bruner's SPDE rocket missions. As a result, the last two months have been divided up pretty evenly between Handy being present at MSU and LPARL. Time at MSU has been spent finishing up several systems projects, and time at LPARL has been spent getting up to speed on UV solar astronomy, space hardware, analysis of UV filters and lining things up to move to the Palo Alto area in January 95. We will be looking for another graduate student to assume the SXT opportunity vacated by Handy. Weber spent September completing his poster paper for the SoHO workshop Page 12 entitled "Differential Rotation in the Solar Corona", co-authored by Acton and Alexander. While the preliminary results indicate no differential rotation of the x-ray corona the error bars on this limited early data set are too large to rule out differential rotation. Weber continues to study this phenomena and shorten his error bars. A secondary concern is for Weber to get up to speed on systems maintenance and operation at MSU when Handy departs for LPARL. Page 13 Yohkoh/SXT Activity Report Stanford Team September/October 1994 In the last two months, Peter Sturrock has been concentrating on the study of ejecta. He attended the SOHO III meeting at Estes Park, and also the recent Coordinated Data Analysis Workshop on "Eruptive Phenomena in the Solar Corona," held in Honolulu. This led Sturrock to reconsider the various forms of energy that can be used to drive ejecta, and the various mechanisms that can be responsible for accelerating material. It seems likely that buoyancy plays an important role in some of these phenomena. Sturrock has found that one may greatly simplify the analysis by introducing an "MHD potential", that is the potential energy of the plasmoid in the presence of the ambient medium. Using this potential, one can easily recover the results of earlier extensive analyses by Kopp and Pneuman, Parker, and others, concerning CMEs, and one can analyze the role of buoyancy in more complex situations such as may be responsible for spicules, surges, sprays, or moving X-ray sources. Jim Klimchuk submitted an article to the Astrophysical Journal, titled "A Comparison of Temperature and Emission Measure Observed in Soft X-rays and Microwaves, and Implications for Coronal Heating". The paper was co-authored with Dale E. Gary. Klimchuk also gave an invited talk at the SOHO III Workshop, titled "Yohkoh Observations Relevant to Mass Ejections". George Roumeliotis submitted an article to the Astrophysical Journal titled "A Novel Maximum Likelihood Method for the Reconstruction of Blurred and Undersampled Soft X-Ray Images". The reconstruction method is being implemented as an IDL routine by a new student, and should be available to the SXT community by the end of the year. One of the illustrative examples in the article provides convincing evidence for the loop-loop interaction scenario. Page 14 YOHKOH/SXT PROGRESS REPORT (25-OCT-1994) for U.C. Berkeley Following the same route that we've used to test the uncertainties in parameters derived from SXT images, we have been using a Monte Carlo technique to calculate the uncertainties in HXT spectral parameters. For non-thermal spectra, typical uncertainties range from 0.3 to 0.5 in spectral index and for super-hot sources, temperature uncertainties range from 7 to 10 MK. These numbers are typical for 10 arcsec sources, and 0.5 second accumulation times, for a large flare on 2-NOV-91. It should be emphasized that these are preliminary results, based on only a few calculations, but these uncertainties are not small (and they represent the best possible numbers for this flare). Care should be taken in interpretation of HXT spectra (a small uncertainty in spectral index can lead to a large uncertainty in the energy of nonthermal electrons). Given the flexibility of the image deconvolution process, it may be possible to reduce the uncertainties. More results from this work will be presented at the Fall AGU meeting in December. Page 15 UNIVERSITY OF HAWAII ACTIVITY REPORT (R. CANFIELD) MAJOR ACTIVITIES FOR THE MONTHS OF SEPTEMBER AND OCTOBER Our most important activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition at Mees, analysis of Yohkoh/Mees data, organization and implementation of the third Hawaii Coordinated Data Analysis Workshop (CDAW), preparation and submission of manuscripts, and completion of a thesis. Operational support for SXT and various campaigns was provided by Hudson and Wuelser at ISAS, as SXT Chief Observers and SSOC tohbans, by Judd, Nitta, and Douglass at Mees (observatory operations), and by Canfield, Jiao, Leka, Metcalf, and Wuelser in Manoa (Mees Yohkoh Duty Scientist). Jiao worked with Z. Mikic (SAIC) in San Diego on numerical techniques, such as 3-D nonuniform staggered mesh for solving MHD problems in Cartesian geometry; semi-implicit method for reducing CFL time step limit on wavelike equation; conjugate gradient method for symmetric positive- definite matrices, etc. They merged three vector magnetograms from Mees and one longitudinal magnetogram from Kitt Peak to produce a hybrid magnetogram that covers AR7222 and AR7220 and smoothed it to prepare the Bz and Jz maps for use as boundary conditions of a 3-D force-free model. They tested constant mass density profile (via height) and then constant alfven speed profile (so mass density ~ B^2) and also nonuniform resistivity and viscosity profiles. They got a surprisingly good result when they compared the computed 3-D force-free B field with the co-aligned SXT images which were taken at times near those of the Mees magnetograms, while the computed 3-D potential field has obvious disagreements. Over the last two months, Leka worked on preparing her dissertation, which has now been submitted to her thesis committee. It includes a detailed roadmap of flux emergence in NOAA AR7260, which was accepted recently in Solar Physics. The bulk of the thesis, however, is an analysis of a few well-observed bipoles in this emerging flux region and their early development with special attention to their magnetic flux and electric current. The numerous independent analysis techniques which were applied to the bipoles all reach the same conclusion: the observed electric currents were not generated by plasma flows in the photosphere. Rather, they were generated either by motions in the convection zone or in the dynamo region, along with their accompanying magnetic fields. Metcalf worked on a new version of the pixon code to reconstruct HXT images. The new code is big improvement and should be online soon. He continued to work on IVM H-alpha data and began a comparison of the IVM data to Nobeyama radioheliograph data. He continued to work with G. Roumeliotis on the extrapolation of photospheric magnetic fields into the corona. They identified a well studied magnetogram from 1989 October 20 as a good starting point. He organized the computer resources for the Hawaii CDAW (workstations and disks). He worked with K. Shibasaki on several projects, including a coalignment of Mees H-alpha coronagraph data with Nobeyama radio images, the analysis of several magnetograms for AR7654 (January 1994), and radio images for comparison with IVM H-alpha Page 16 polarization data. He worked with L. Harra on the analysis of a magnetogram from AR7590. He worked with N. Nitta on the analysis of a several magnetograms from AR7515, including upgrading the software used for the reduction of IVM magnetograms. Wuelser spent the month of September at ISAS. He helped out with operations and served as SXT chief observer during a shortage of LPARL personnel. The stay at ISAS was also an opportunity to work with Nishio, Kosugi, and Hudson on the Mercury transit observations. The effort led to a better value for the SXT roll angle and the SXT plate scale. Wuelser also revisited and updated the algorithms which calculate the spacecraft pointing database. A severe error was found and corrected (see memo of Sept. 27 distributed by Freeland). In preparation for the Hawaii Coordinated Data Analysis Workshop, Wuelser made a list of radio type II events with good Yohkoh and Mees coverage. He did a quick survey of about 10 of those events and presented the results at the beginning of the workshop. During the workshop, Sakao and Wuelser worked together on a particularly interesting event which occurred near the solar limb on January 16, 1994. A large, pre-existing soft X-ray loop erupted well before the impulsive hard X-ray burst, but no filament eruption could be seen in H-alpha. The hard X-rays showed impulsive footpoint sources and a loop-top source. Most puzzling is the fact that the hard X-ray loop top source appears below, and not above the hottest part of the soft X-ray loop. Hudson supported Yohkoh operations, and prepared for the CDAW by working up his material on the 21 Feb. eruptive event. He assisted Jean-Pierre Wuelser in his exploitation of the Mercury transit data for SXT alignment calibration. It now appears that SXT absolute alignment (relative to the solar limb) has been established to a precision better than one pixel, limited mainly by the quantization error of the HXA sensor that is the fundamental limb reference. Most of Hudson's science time during this period was devoted to the Annual Reviews article he is writing with J. Ryan. This is complete except for figures and will be submitted in November. As is usual during the process of writing such a review, one learns a lot, and for what it's worth here is a sentence or two on the nicest nugget: S. White and co-authors have identified a new class of mm-wave flare events which have an "impulse response" behavior characterized by an extremely fast linear rise and ~20-sec exponential decay. In one case the spectrum could be determined to be almost absolutely flat beginning with a sharp cut-on between 5 and 8 GHz. There is no current explanation for these events, which are clearly very different. They are extremely compact and therefore probably low-lying. Hudson speculates that they are related to the hard-spectrum HXT events and/or to the Rieger "electron rich" gamma-ray events, which are of course much brighter. This set of unexplained results, plus the Masuda result on impulsive "loop-top" brightenings, makes the Yohkoh era one of major progress for high-energy solar flare observations. Canfield organized and participated in the CDAW and worked on two Page 17 projects. First, he worked with K. Shibata, T. Yokoyama, and M. Shimojo on surges and jets in AR7260. A rough draft of a paper was completed, describing a morphological model which explains the relationship of the observed X-ray jets and H-alpha surges to one another, to satellite spots and their motion, to bright X-ray loops, to H-alpha footpoints, to moving H-alpha blueshift features, to the spin of the surge, to H-alpha redshifts, and to approaching H-alpha footpoints. Second, he worked with S. Martin and K. Shibata on a dataset of simultaneously observed H-alpha and X-ray eruptive prominences from Mees and Yohkoh data. Thus far, twelve events were identified; all eruptive events are seen in both X-rays and H-alpha, but other types of events were noted that were not. PLANS FOR NOVEMBER AND DECEMBER Jiao is now reviewing and studying on Z. Mikic materials on numerical methods and will begin to work on additional active regions. Leka will defend her dissertation on 1 November, then travel to Japan to support Yohkoh operations. She will be SSOC tohban for the week beginning 21 November. While in Japan, she will re-work chapter V of her thesis to submit as a paper before moving to her post-doc position at NCAR in December. Metcalf plans to continue the analysis of the IVM H-alpha polarization data in conjunction with the Nobeyama data. He will complete work on a new version of the HXT pixon code. He will start work on a new version of the SXT pixon code. He will continue to work with Roumeliotis on the extrapolation of photospheric magnetic fields into the corona. Wuelser will continue to work on two collaborative studies: with Bastian on the August 20, 1992 flare that was well observed by Yohkoh, Mees and the VLA, and with Sakao on the January 16, 1994 flare (discussed above). He also plans to write up a study on chromospheric evaporation and energetics in several large flares. Hudson's top priorities for this period include assisting F. Farnik with the completion of two major works resulting from his stay at ISAS: one on the hard-spectrum flares of October 1993, and one on a search for flare precursors. He hopes also to submit a paper on the Feb. 21 event during this time period and would like to help Wuelser with a projected manuscript on the Mercury transit, to be co-authored with Nishio, Kosugi and others who have contributed to this complicated and successful observation. Canfield will work with K. Shibata, T. Yokoyama, M. Shimojo, and K. Reardon on surges and jets, and hope to have a paper ready for submission by the end the year. PUBLICATIONS AND PRESENTATIONS DURING SEPTEMBER AND OCTOBER Papers accepted Page 18 "Comment on 'The Solar Flare Myth'", Hudson, H.S., Strong, K.T., and Haisch, B.M., JGR "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 published "A Gigantic Coronal Jet Ejected from a Compact Active Region in a Coronal Hole" ApJ 431, L51. "Thermal Plasmas in the Solar Corona: The Yohkoh Soft X-Ray Observations," H. Hudson, Proc. Kofu Symposium, NRO Report 360, 1994, p 1. "Hard and Soft X-Ray Observations of a Super-Hot Thermal Flare of 6 February, 1992," T. Kosugi, T. Sakao, S. Masuda, H. Hara, T. Shimizu, and H. Hudson, Proc. Kofu Symposium, NRO Report 360, 1994, p 127. "Temperature Analysis of the Post-Flare Loops of June 25-26, 1992," B. Anwar, E. Hiei, H. Hudson, L. Acton, J. Lemen, and T. Metcalf, Proc. Kofu Symposium, NRO Report 360, 1994, p 137. "H-alpha and X-Ray Signatures of Chromospheric Heating Observed in Solar Flares," J.-P. Wuelser, R. Canfield, T. Sakao, S. Masuda, T. Kosugi, and S. Tsuneta, Proc. Kofu Symposium, NRO Report 360, 1994, p 195. "Multiwavelength Observations of a Solar Flare," S. White, A. Silva, I. de Pater, R. Lin, D. Gary, H. Hudson, J. Doyle, M. Hagyard, and M. Kundu, Proc. Kofu Symposium, NRO Report 360, 1994, p 203. "Evidence for Both Electron Acceleration and Direct Heating in Solar Flares," B. Dennis, G. Holman, H. Hudson, T. Kosugi, K. Strong, and D. Zarro, Proc. Kofu Symposium, NRO Report 360, 1994, p 217. "Determining Point Spread Function of Space Observations Using Bid Algorithm," M. Karovska, and H. Hudson, Proc. Kofu Symposium, NRO Report 360, 1994, p 327. "Metric Type III Bursts from Flaring X-Ray Bright Points," M. Kundu, K. Strong, M. Pick, K. Harvey, S. Kane, S. White, and H. Hudson, Proc. Kofu Symposium, NRO Report 360, 1994, p 343. "Study of Active Region Magnetic Field Structures Using VLA Radio, Yohkoh X-Ray and Mees Optical Observations," N. Gopalswamy, E. Schmahl, M. Kundu, J. Lemen, K. Strong, R. Canfield, and J. de la Beaujardiere, Proc. Kofu Symposium, NRO Report 360, 1994, p 347. Page 19 "A Search for `Black-Light Flares'," L. van Driel-Gesztelyi, H. Hudson, B. Anwar, and E. Hiei, Proc. Kofu Symposium, NRO Report 360, 1994, p 375. "Flares in Active Region NOAA 7260 - Role of Emerging Flux," N. Nitta, L. van Driel-Gesztelyi, K. Leka, D. Mickey, T. Metcalf, J.-P. Wuelser, K. Ichimoto, T. Sakurai, and K. Shibata, Proc. Kofu Symposium, NRO Report 360, 1994, p 385. "Analysis of Three Yohkoh White-Light Flares," H. Hudson, L. van Driel-Gesztelyi, and T. Kosugi, Proc. Kofu Symposium, NRO Report 360, 1994, p 397. Page 20 Solar Physics Research Corporation Activity Report Karen L. Harvey October 25, 1994 Activity the last two months are as follows: 1. An XBP campaign was requested and scheduled from September 26-October 1, 1994. The objective of this run is to continue obtaining observations to study the variations and association of He I 10830 dark points to 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. Like these previous efforts, this run also suffered from extremely poor weather conditions at Kitt Peak and Big Bear Solar Observatory, and not as marginal weather at Mees. We plan to request additional collaborative Yohkoh/SXT observations around the third week in November. 2. Continuing 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 areas. 3. Continuing the updating of the bibliography of Yohkoh papers. 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. Continuing work on the analysis of the 14 April 1994 arcade event with David Alexander, Hugh Hudson, and Alan McAllister. This work was presented by David Alexander at the Estes Park/SOHO meeting in late September.(5) Attended the CDAW workshop at the University of Hawaii on the subject of eruptive events. Participation involved examining the Yohkoh/SXT data targeting events that produced CMEs observed by the SWICS instrument onboard Ulysses. This work was done with Jim Lemen and Toni Galvin and will in the future with Hugh Hudson. Our plans are to expand the list of events, both from the Ulysses data, from the SXT observations, and from the NSO/KP He I 10830 spectroheliograms. The study objective is to identify characteristics of the source events on the Sun as related to the chemical composition in the CMEs measured by SWICS. Page 21 ------------------------------------------------------------------------------- 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 November 1994 October 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 October 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 | 21 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office