Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for March 1995) 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 This was a sad month for the Yohkoh team. First we lost Dr. Chung-Chieh Cheng (NRL) to illness, and then one of the KSC tobans, Dr. Koyama (Kinki University), was killed in a tragic accident while working at KSC. The candidates for a Post-doc position have all been evaluated and an offer has gone out to the leading individual. On the CBS program Sunday Morning an image from SXT was shown last Sunday in one of the transitions between the news features where normally only artistic interpretations of the Sun are utilized. We were responsible for this event. << Solar Activity >> The Sun remained moderately active this month producing 16 small flares (C-class) and one moderately large flare. Most of these flares seemed to come from a series of vigorous but small active regions that flared sporadically as they crossed the disk. The largest flare, an M2, peaked at 16:40 UT on 22 March and its origin was unidentified from ground-based reports but Yohkoh identified it as coming from a large active region behind the east limb of the Sun (see the bottom left panel of the accompanying X-ray images from Yohkoh). The region was later numbered as NOAA AR7858. This flare Page 2 was spectacular, as seen by the SXT PFI images. It was plainly a long-lasting, cusp-shaped, flare loop arcade, but the cusp was thin and bent back in a long, elegant curve and seemed to be connected back to the Sun. This is not the usual picture of post-flare loops! The most striking thing about this month's full disk images were the extensive areas of coronal holes, the dark areas. The largest of these lay near the poles of the Sun. There were also several smaller, isolated coronal holes near the equator. << Campaigns >> SXT intensified its campaign of filling in its white-light leak data bases for each of the filters by taking a series of terminator images. As the amount and pattern of white-light background is dependent on Yohkoh's pointing we have to build up a matrix of images for several offpoints and in several filters. The programme is basically automatic requiring scheduling by the SSOC tobans and the Chief Observer. This was progressing well until we realized that the recovery of SXT from SEUs can be thwarted if it is done during an attempt at taking a terminator image. So we have had to restrict terminator images to non-KSC contact times. This has cut the rate at which this calibration exercise will progress. We are planning campaigns to observe filaments and XBPs as well as support HRTS, SERTS, SPARTAN, and Ulysses' passage over the nothern pole of the Sun in the coming months . << Science >> During March the Astronomical Society of Japan held one of its biannual meetings at a University near NAOJ. Many interesting talks featuring Yohkoh and Nobeyama data were given. It was particularly pleasing to see so many young and enthusiastic Japnaese students studying solar physics. Preparations are proceeding for the IAU symposium to be held near Tokyo in May. Several of us are preparing talks for the American Geophysical Union meeting's special session on the "Flare Myth" and for the Solar Physics Division Meeting in Memphis. << Publications>> The following list is an incomplete listing of work in progress on papers and presentations that include scientists that are supported by the NASA SXT contract. Page 3 - Papers Published (2) - "The Large Scale Coronal Eruptive Event of 14 April 1994" D. Alexander et al., Proceedings of 3rd SoHO Workshop, "Solar Dynamic Phenomena and Solar Wind Consequences", pp187-190. "Differential Rotation in the Solar Corona", M. Weber et al., Proceedings of 3rd SoHO Workshop, "Solar Dynamic Phenomena and Solar Wind Consequences", pp405-408. - Papers accepted (0) - - Papers Submitted (4) - "Why We Study Solar Flares" H. Hudson, EOS "VLA and Yohkoh Observations of an M1.5 Flare" N. Gopalswamy, J.-P. Raulin, M. R. Kundu, N. Nitta, J. R. Lemen, R. Hermann, and D. Zarro submitted to ApJ "Microwave and Hard X-ray Observations of Footpoint Emission from Solar Flares" M. R. Kundu, N. Nitta, S. M. White, K. Shibasaki, S. Enome, T. Sakao, T. Kosugi and T. Sakurai submitted to ApJ "Metric Type III Bursts Associated with Soft X-ray Jets" J.-P. Raulin, M. R. Kundu, N. Nitta, S. S. Hudson and A. Raoult submitted to A & Ap - Presentations (1) - "Soft X-Ray Loops and Wave Heating," J. A. Klimchuk, presented at the NASA/GSFC Workshop on Wave Heating, March 13, 1995 - Abstracts submitted(8) - "The Heating of Coronal Loops," J. A. Klimchuk and L. J. Porter, to be presented at the Spring 1995 AGU Meeting, Baltimore. "Coronal Activity Associated with CMEs and Flares" K.T. Strong and H. Hudson, to be presented at the Spring 1995 AGU Meeting, Baltimore. "The Cross Sectional Properties of Coronal Loops," J. A. Klimchuk, to be presented at the 1995 SPD Meeting, Memphis. "A Statistical Study of X-ray Bright Points", K.T. Strong and K. Harvey, to be presented at the 1995 SPD Page 4 Meeting, Memphis. "The Solar Origins of Two High-Latitude Interplanetary Disturbances" H. Hudson, L. Acton, D. Alexander, K. Harvey, K. Kurokawa, S. Kahler and J. Lemen "Comparison of Yohkoh X-ray Coronal Events with Ulysses Interplanetary Events" J. Lemen, L. Acton, D. Alexander, A. Galvin, K. Harvey, J. Hoeksema, X. Zhao and H. Hudson "The solar/interplanetary event of 14 April 1994 observed by Yohkoh/SXT" D. Alexander, K. Harvey, T. Hoeksema, H. Hudson, X. Zhao "Yohkoh/SXT Soft X-ray Observations of Sudden Mass Loss" H. Hudson, L. Acton, D. Alexander, S. Freeland, J. Lemen and K. Harvey << Public Use of SXT Images >> We continue to submit and have published our monthly article on solar weather in "Sky & Telescope". << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function well with XX Single Event Upsets (SEUs). No significant degradation in the instrument has occurred since the loss of the front thermal shield in 1992. SXT experienced a normal level of SEU events during the month: SXT bitmap error 5-Mar-95 10:30 UT SXT warm reset 25-Mar-95 (last pass - recovered 27-Mar-95) SXT frame gate error 28-Mar-95 Pass 4 The SXT under went one of its periodic CCD bakeouts from 1-3 March 1995 to help remove contaminants that condense onto its surface. We have successfully started to use Wallops ground station for Yohkoh data dumps; this has relieved some of the data loss due to scheduling conflicts with ASCA and SFU. Page 5 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot ------------------------------------------------------------------------------ Thru Oct-92 78850 37943 288731 148277 437008 158479 26.31 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 7079 2552 25131 2855 27986 10677 27.62 Oct-94 7244 2497 25868 5884 31752 10319 24.53 Nov-94 6569 1941 26243 1956 28199 9293 24.79 Dec-94 6429 2456 26763 2583 29346 11904 28.86 Jan-95 2922 887 11115 105 11220 3793 25.26 Total 268865 116693 1157365 331463 1488828 579010 28.00 Number of Full Frame Images Received: 268865 Number of Observing Region Images Received: 1488828 Total: 1757693 Approximate Number of Shutter Moves/CCD Readouts: 3060403 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 (%) -------------------------------------------------------------------------------- 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 18.3 N/A Oct-94 47.34 631.3 64974 4346 19.0 N/A Nov-94 47.64 642.4 70877 4703 20.4 N/A Dec-94 47.82 649.1 74246 4917 21.5 N/A Jan-95 48.77 684.6 94799 5572 20.3 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-MAR-95 and 31-MAR-95 ACTON 1-MAR-95 * 4-MAR-95 4 (total of 4 days) FREELAND 21-MAR-95 31-MAR-95 * 11 (total of 11 days) HUDSON 1-MAR-95 * 1-MAR-95 1 12-MAR-95 31-MAR-95 * 20 (total of 21 days) LINFORD 1-MAR-95 * 15-MAR-95 15 (total of 15 days) SHING 1-MAR-95 * 22-MAR-95 22 (total of 22 days) STRONG 1-MAR-95 31-MAR-95 31 (total of 31 days) WEBER 1-MAR-95 * 31-MAR-95 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 135 days for 7 people NOTE: The "*" signifies travel that actually ends after 31-MAR-95 SXT Foreign Travel between 1-APR-95 and 30-APR-95 ACTON 29-APR-95 30-APR-95 * 2 (total of 2 days) FREELAND 1-APR-95 * 20-APR-95 20 (total of 20 days) HUDSON 1-APR-95 * 1-APR-95 1 9-APR-95 16-APR-95 8 22-APR-95 30-APR-95 * 9 (total of 18 days) LEMEN 3-APR-95 30-APR-95 * 28 (total of 28 days) WEBER 1-APR-95 * 1-APR-95 1 (total of 1 days) WUELSER 1-APR-95 28-APR-95 28 (total of 28 days) ---------------------------------------------------------------- Grand Total of 97 days for 6 people NOTE: The "*" signifies travel that actually ends after 30-APR-95 Respectfully submitted, Keith T. Strong Frank Friedlaender Page 8 ------------------------------------------------------------------------------- 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 April 1995 March 1995 |------------------------------- | 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 March 1995 |------------------------------- |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 | 8 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office