Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for June 1996) 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 Toward the end of the month, requests were received from NASA asking us to propose how we would operate at approximately 50% of current costs to complete the 11-year solar cycle through the year 2002. A budget and a plan has been prepared. There has been some additional iteration, but we are looking forward to have the opportunity to operate throughout the cycle. The Yohkoh team at Lockheed Martin was nominated for the NOVA award, one of the highest recognitions that is granted by Lockheed Martin to a team or an individual. Although the Yohkoh team did not win the award, the nomination itself confers a recognition by Lockheed Martin's management that the Yohkoh program is being conducted in a highly successful manner. << Solar Activity >> Solar activity has continued to wax and wane around A-level, with B-class flares not being uncommon. The three largest flares of this period have exceeded B.3, but no C-class flares have been evident in the GOES record. It appears that the greater proportion of active regions recently has been in the northern hemisphere, for both old- and new-cycle complexes. The new-cycle region (#7972) at N30 created coronal loops and was still visible at the end of the reporting period. The active longitudes seem to be mostly 180 degrees apart, with some exceptions. Page 2 << Campaigns >> The month of June was relatively calm month for Yohkoh operations, mainly because of the fact that many scientists were preparing to attend the AAS/SPD meeting in Madison, Wisconsin. There was a "micro-campaign" (coordinated by George Fisher) with SOHO/SUMER and SOHO/CDS to observe NOAA AR 7968. We also participated in a longer campaign (June 2 to June 10), directed by Brigitte Schmieder with Meudon and SOHO/SUMER and SOHO/CDS, to observe coronal loops. In general there are now many opportunities for Yohkoh and SOHO to work together, and we would like to stay as closely in touch as possible. For Yohkoh operations, there is a text file accessible with "finger campaign@isass0.solar.isas.ac.jp | more" or the Web at "http://www.space.lockheed.com/SXT/homepage.html". << Science >> A highlight of the month was the AAS/SPD meeting in Madison, Wisconsin. Several posters presented Yohkoh data and results. Brian Handy (MSU) had a poster that compared EIT and Yohkoh images. He looked at the coronal hole boundaries observed during the SOHO south pole observations made earlier this year. He also compared the polar plumes and the bright points observed with the two instruments in the different temperature regimes. There was a lot of interest in his poster, including that of the newly elected AAS President. Jean-Pierre Wuelser presented a poster with Don Mickey (U of Hawaii) entitled "Vector Magnetic Field Observations of the Solar South Pole". The poster focussed on how the magnetic field looks like at the footpoints of polar coronal plumes. The main findings are: - The strongest magnetic features in the polar coronal hole are located at the footpoints of plumes seen in the EUV. - The footpoint features are essentially unipolar. - The field inclination is close to radial, whereas plumes usually appear to be pushed away from the radial direction, towards the equator. This discrepancy may be due partly to a field direction change between the photosphere and the corona, and partly to a filling factor effect in the magnetic field measurement. James Lemen presented a poster on the dimming corona that was also the subject of a companion poster by Dave Webb et al. It appears that the mass estimates associated with the dimming of the corona at the start of various large scale eruptive events is consistent with the mass observed in typical white light CMEs. Plans are being made to write up these results for ApJ Letters. Serge Savy presented a poster at the Madison meeting entitled "Soft X-Ray Pre-flare Brightenings". Between SXT Chief Observer duties, Serge also worked to prepare for the Cospar meeting which will be held this July in England. Page 3 Nariaki Nitta presented a contributed talk on "Large-Scale Loops in AR 7260 and a Superhot Flare." Nariaki has been tracking the history of flux emergence in AR 7260. He is trying to study the formation of large-scale loops that eventually develop into an LDE. Part of the whole structure was bright for long time and became a site of a superhot flare. He is trying to understand these loops in terms of the "quasi-separatrix layer", a new concept from 3-D reconnection models Greg Slater returned from ISAS. Among other things, he installed the new SCSI controllers to enable the new disks that Prof Ogawara purchased for the NASA-owned ISASS0 and ISASS1 computers. Greg and others worked with Jingxiu Wang, who is visiting from Beijing, on the apparent shrinking of coronal loops in an active region (AR 7420) during February 1993. Tom Metcalf arrived in California at the beginning of the month after quickly settling in continued to work with G. Fisher and D. Longcope on a project comparing SXT non-flare images and photospheric vector magnetograms. The study looks for correlations between soft x-ray intensity and various measures of non-potentiality in the magnetograms in an effort to understand the mechanisms of coronal heating. Interestingly, photospheric electric currents seem to play no role. Tom also has been working on pixon HXT light curves for the 1992 January 13 limb flare with David Alexander. They are looking at differences in the light curve for the loop top source computed with the two reconstruction algorithms. They have done some simulations of the Masuda event and the preliminary results show no surprises. A report on the simulation results will appear soon. Tom has installed a new version of the pixon code which is considerably faster than the old version (but it's still pretty darn slow). Gary Linford worked very hard to support the various public outreach needs. He also worked (remotely and with Tim Roethig) to support Greg Slater's efforts to install the new disks on the ISASS0 and ISASS1 workstations. This should help to improve the performance and reliability of the computer network in Japan for operations. Finally, Gary spent some time working on possible compression schemes that will enable the Yohkoh archive to be written to CD-ROM. We are currently distributing the archive on 8-mm tapes, but we plan to change to CD-ROM in the near future. << Public Use of SXT Images >> We are continuing to make Yohkoh/SXT images available for a variety of uses. Efforts continue to make selected images available on the Lockheed SXT WWW homepage (http://www.space.lockheed.com/SXT). We continue to receive requests for the Yohkoh posters (#2 and #3) by way of the form on the SXT homepage. Currently we receive requests via our homepage at the rate of 2 or 3 per day. The WEB access statistics in June were 32000 accesses and 678 Mbytes transferred, about the same as Page 4 for May. Gary Linford had the Lockheed Martin print shop print 12K more full-sized versions of the Changing Sun poster, and 10K more of the 2nd poster (the one with the 8-May-92 image). The mini version (A-sized) of the Changing Sun is very popular and is being distributed in various ways. Greg Slater, Gary Linford, Keith Strong and James Lemen met to discuss the content of a new SXT video. This might be one item that can be used to highlight the upcoming fifth anniversary of the Yohkoh launch. Keith has produced a story line that will become the basis of the video. We expect that it will include a voice-over. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. There has been no further increase in the SXT stray light since 16-Aug-1995. The quiet patrol image has been changed to Al/Mg (DPE=17) to try to improve the performance of the active region selection algorithm for times when the Sun is very quiet. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT bitmap error 16-Jun-96 Pass 4: 960616-0827 recovered in the same pass SXT bitmap error 17-Jun-96 Pass 1: 960617-0514 recovered in the same pass SXT error 1 SEC 22-Jun-96 Pass 4: 960622-0721 recovered in the fifth pass This was probably an SEU error. SXT bitmap error 24-Jun-96 Pass 1: 960624-0308 recovered in the same pass Page 5 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Mar-94 203135 92924 871876 302386 1174262 456426 27.62 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 6870 2349 26103 1699 27802 10211 26.86 Feb-95 6556 2545 23635 3825 27460 10111 26.91 Mar-95 5915 2082 21485 3448 24933 8485 25.39 Apr-95 6244 2266 22946 4493 27439 9688 26.09 May-95 7084 2884 29617 2647 32264 15331 32.21 Jun-95 7210 3087 25251 307 25558 12045 32.03 Jul-95 6418 4145 21180 1639 22819 15109 39.84 Aug-95 7683 2597 26115 2181 28296 10537 27.13 Sep-95 6546 2853 22006 1753 23759 10433 30.51 Oct-95 6937 3502 22177 3853 26030 13044 33.38 Nov-95 5745 2944 21252 517 21769 12119 35.76 Dec-95 6163 2615 24059 901 24960 11652 31.83 Jan-96 6474 2530 27015 1708 28723 14151 33.01 Feb-96 6200 2581 21380 890 22270 10773 32.60 Mar-96 6908 2869 25437 1460 26897 12274 31.33 Apr-96 7172 2124 45445 671 46116 18848 29.01 May-96 6925 2426 30272 1089 31361 12367 28.28 Jun-96 130 163 418 0 418 624 59.88 Jul-96 0 0 0 0 0 0 0.00 Total 379123 162368 1582043 364439 1946482 783019 28.69 Number of Full Frame Images Received: 379123 Number of Observing Region Images Received: 1946482 Total: 2325605 Approximate Number of Shutter Moves/CCD Readouts: 4060497 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 -------------------------------------------------------------------------------- Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) 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 46.98 617.6 57624 4050 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 48.55 676.7 89758 5457 20.0 N/A Feb-95 48.70 682.1 92457 5781 25.2 / 3 20.5 N/A Mar-95 48.35 668.9 85527 5271 19.4 N/A Apr-95 48.72 682.8 93904 5627 19.1 N/A May-95 48.73 683.4 94000 5820 18.8 N/A Jun-95 49.08 696.3 100780 6281 19.6 N/A Jul-95 49.34 706.2 106408 6628 18.1 N/A Aug-95 49.72 720.4 114414 7101 19.5 N/A Sep-95 49.79 723.1 115165 7222 19.6 N/A Oct-95 50.29 741.9 126452 7911 20.2 N/A Nov-95 50.11 735.1 122163 7814 25.2 / 2 20.3 N/A Dec-95 50.19 737.9 123705 7927 22.6 N/A Jan-96 50.81 761.3 136197 8888 21.5 N/A Feb-96 50.67 755.8 133263 8705 22.5 / 2 21.5 N/A Mar-96 50.85 762.9 136982 8973 20.3 N/A Apr-96 51.14 773.6 142250 9500 19.9 N/A May-96 51.16 774.4 140697 10018 19.1 N/A Jun-96 N/A N/A N/A N/A 19.8 N/A Jul-96 N/A N/A N/A N/A 0.0 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-JUN-96 and 30-JUN-96 ALEXANDER 22-JUN-96 30-JUN-96 * 9 (total of 9 days) HUDSON 1-JUN-96 * 30-JUN-96 * 30 (total of 30 days) NITTA 1-JUN-96 * 5-JUN-96 5 (total of 5 days) SAVY 15-JUN-96 30-JUN-96 * 16 (total of 16 days) SLATER 1-JUN-96 * 11-JUN-96 11 (total of 11 days) WEBER 1-JUN-96 30-JUN-96 * 30 (total of 30 days) ---------------------------------------------------------------- Grand Total of 101 days for 6 people NOTE: The "*" signifies travel that actually ends after 30-JUN-96 SXT Foreign Travel between 1-JUL-96 and 31-JUL-96 ALEXANDER 1-JUL-96 * 20-JUL-96 20 (total of 20 days) HUDSON 1-JUL-96 * 21-JUL-96 21 29-JUL-96 31-JUL-96 * 3 (total of 24 days) LEMEN 8-JUL-96 31-JUL-96 * 24 (total of 24 days) SAVY 1-JUL-96 * 10-JUL-96 10 24-JUL-96 31-JUL-96 * 8 (total of 18 days) WEBER 1-JUL-96 * 1-JUL-96 1 (total of 1 days) ---------------------------------------------------------------- Grand Total of 87 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-JUL-96 Respectfully submitted, James R. Lemen Frank M. 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 | 8 July 1996 June 1996 |------------------------------- | 6. PERFORMING ORG | CODE: O/91-30 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- J. R. Lemen | 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 - 40801 -----------------------------------------------|------------------------------- 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 June 1996 |------------------------------- |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