Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for August 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 The five year milestone of the Yohkoh launch passed this month. Various materials commemorating the program are still in preparation and will be distributed when they become available. The program is fully funded for FY 96 and we are looking forward to continue operations throughout the next FY with FY97 funding. << Solar Activity >> A large active region which produced an X flare in July (7978) reappeared twice in August. During its second and third rotations it was 7981 and 7986, respectively. During the region's second passage it remained at an almost constant X-ray brightness, but no large flares. During the third passage of the region a major LDE flare event on 22 August that reached the C4.5 level, even though the active region was 15-20 degrees beyond the limb (occultation height >20,000 km). Although the flaring activity died out, the coronal structure was profoundly changed with this region's appearance - a much brighter streamer/arcade structure, and a coronal hole channel advancing downwards from the north polar hole. The region's near-uniqueness while on the disk makes it a good region to study for technical purposes. For example, the BCS wavelength offset can be calibrated as a function of orbital phase and the flare-microflare frequency distribution, can be measured, which appeared to change with time. << Campaigns >> Page 2 During this month Yohkoh began support for the SOHO JOP 44 entitled "Global coronal Campaign". This JOP will continue until mid-September and should provide an important database for SXT observations of the quiet corona and help us track its large scale structure. Sarah Gibson (GSFC) and Douglas Biesecker (Birmingham) are coordinating the campaign on the SOHO side. The New Brunswick and SERTS rockets may fly in September. For Yohkoh operations, there is a text file accessible on the Web at http://www.space.lockheed.com/SXT/html2/First_Light.html which also lists the current SXT Chief Observer, or the unix command: # finger campaign@isass0.solar.isas.ac.jp | more The SOHO target planning is available from: http://sohowww.nascom.nasa.gov/operations/targets/today << Science >> A highlight of this past month was the Chapman Conference on "Coronal Mass Ejections -- Causes and Consequences". The conference was hosted in Bozeman, MT at Montana State University and was very successful with approximately 130 scientists in attendance. Prof Eijiro Hiei Meisei University visited Lockheed Martin for a part of day and held discussions with various members of the Yohkoh/SXT team. We discussed the work that Hudson and Lemen are doing on the coronal dimming events of 21 February 1992 and 28 August 1992. Prof Hiei's student is looking at dimming events that have occurred on the disk. Such events are more difficult to analyze, but several of them show good evidence of dimming. When more events have been studied it will be interesting to see if there is a correlation between "fast CMEs" and the amount of coronal dimming observed. At the beginning of the month, Jingxiu Wang, who visited ISAS for 3 months returned to his home in Beijing China. The day he left his paper was submitted to ApJ for publication entitled, "Shrinkage of Coronal X-ray Loops" by J. Wang, K. Shibata, N. Nitta, G. L. Slater, S. K. Savy and Y. Ogawara. The author list represents those who particularly were involved in collaboration with Wang during his very productive visit. Nariaki Nitta continues to work on his superhot flare paper. He is now using three-filter SXT observations to investigate the thermal distribution of the flaring plasma. Nitta is also working with Mukul Kundu (U. of Maryland) on the observed negative correlation of type III radio bursts and two-sided X-ray jets. Tom Metcalf continues to work with George Fisher and Dana Longcope on the SOHO mini campaign data, which involves SXT, Sumer, and Mees photospheric vector magnetograms. The goal of the project is to study transient brghtenings. Metcalf has made a thorough comparison of MEM and Pixon reconstruction techniques for HXT observations of the 13 Page 3 January 1992 flare, one of the well known Masuda events. Jean-Pierre Wuelser is working on vector magnetogram data taken with the Mees Solar Observatory IVM on 23 August 1996 in support of SOHO JOP 48. This JOP had as its goal, the study of polar plumes, similar to the one which was conducted in March of this year. Results from the earlier campaign were presented at the SPD meeting in Madison. Wuelser was also preparing to travel to ISAS for the month of September were he will be taking over as the SXT chief observer for part of the time. << 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 August were 36800 accesses and 830 Mbytes transferred. Work is progressing on the fifth anniversary briefing package, a new video, and a business card that will show a Yohkoh image on one side and our web address on the back with a Sun-earth illustration. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. An increase in the straylight occurred on 25 August 1996. Further investigation leads us to believe that there has been another entrance filter failure. The increase in the straylight is of the order 30%. The previous occasion that this occurred was on 16 August 1995. The terminator image program immediately acquired the necessary images to correct the straylight and so there has been no interruption in the observing programs of the SXT. 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. Yohkoh was not able to observe for a couple of days when a typhoon which went over Kagoshima prevented operation of the 20- meter antenna. On another occasion, SXT was also not operated for about one day as the result of a operation error at KSC. Towards the end of the month it was noted that the pointing solutions obtained with the HXA (the HXT aspect sensor) were not as reliable as before. Upon investigation, it was determined that the intensity as measured by the HXA has decreased somewhat over the past five years, and therefore, an adjustment to the threshold values is necessary. This will be performed in the near future. SXT experienced a normal level of Single Event Upset (SEU) events during the Page 4 month: SXT bitmap error 5-Aug-96 Pass 1: 960805-0618 recovered in the same pass SXT bitmap error 6-Aug-96 Pass ?: 960806-0414(?) recovered in the same pass SXT bitmap error 12-Aug-96 Pass 5: 960812-0723 recovered in the same pass SXT bitmap error 31-Aug-96 Pass 1: 960830-1342 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 May-94 216347 98344 919843 308816 1228659 479626 27.76 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 7522 2716 31984 1536 33520 14489 30.18 Jul-96 5954 1995 29886 4769 34655 12427 26.39 Aug-96 844 194 3162 461 3623 907 20.02 Sep-96 0 0 0 0 0 0 0.00 Total 393313 167110 1646657 371205 2017862 810218 28.65 Number of Full Frame Images Received: 393313 Number of Observing Region Images Received: 2017862 Total: 2411175 Approximate Number of Shutter Moves/CCD Readouts: 4202650 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 (%) 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 51.56 789.2 147705 10634 20.7 N/A Jul-96 57.45 1010.2 146293 12228 19.8 N/A Aug-96 N/A N/A N/A N/A 21.2 N/A Sep-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-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 SXT Foreign Travel between 1-AUG-96 and 31-AUG-96 HUDSON 1-AUG-96 * 8-AUG-96 8 16-AUG-96 31-AUG-96 * 16 (total of 24 days) SAVY 1-AUG-96 * 31-AUG-96 * 31 (total of 31 days) JIAO 1-AUG-96 31-AUG-96 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 86 days for 3 people NOTE: The "*" signifies travel that actually ends after 31-AUG-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 | 10 September 1996 August 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 August 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