Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for April 1998) 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 Although some progress is being made on the definitization of the operational amendment for 1998, it did not get completed this month. The Co-I's, however, are continuing their support and we are maintaining a strong technical presence in all areas. << Solar Activity >> At the beginning of April, solar activity was moderate with many C-class flares. They were earlier produced in AR 8183 and AR 8185/8189 then in AR 8190/8191. Except for AR 8183, the activity centers were in the southern hemisphere. Moreover, a region at the back of the Sun seemed to be quite visible, occasionally presenting nice shows of dynamic motion. At mid-month, solar activity continued to be low to medium with the GOES background level staying in the B2-B4 range. The large active region complex including AR 8194 stayed quiet and moved toward the southwest limb, where it finally showed a large-scale expansion (between 17-Apr-98 23 UT and 18-Apr-98 06 UT). On the southeast limb, an eruptive event was seen from the back side on 16-Apr-98 at 04 UT. On the northern side, AR 8203 grew rapidly on 15-Apr-98 and reached the level of producing four high C-class flares in 20 hours. But the growth appeared to stop. In the second half of April, approximately a dozen C or greater events occurred. These included two rather spectacular over-the-limb events, an M1 proton flare in the SW (April 20) and an X1 in the SE (April 23). The latter originated about a day beyond the limb and had the characteristically sluggish Page 2 hard X-ray variations associated with an over-the-limb event. It was caught with a new SXT flare observing sequence, which emphasizes ejections, and furthermore the preflare PFIs were properly situated to see the beginnings of the ejection. The coverage was excellent, including Nobeyama. The April 20 event is the subject of a weekly SXT science nugget. Again, a beautiful ejection was observed. Solar activity was moderate as April closed, with one X flare (Apr 27) and two M flares (Apr 29 and May 01). All three were generated by active region NOAA 8210, the first two (and maybe the third?) were associated with Earth-directed CMEs. << Campaigns >> There were no formal campaigns this month. << Science >> The presence of ISAS Visiting Professor H. Aurass (from Potsdam) stimulated a great deal of new discussion. He is probably the longest-term visitor really knowledgeable with meter-wave radio observations, and because SXT and the meter wavelengths both look at regions of similar plasma density, but by very different techniques, comparisons have always been one of the more exciting fields for Yohkoh data analysis. The third SOHO-Yohkoh CDAW (Coordinated Data Analysis Workshop) took place the week of April 4. Everything worked fine, with perhaps 25 workstations simultaneously cranking away on things related to the theme, magnetic connectivity between the corona and photosphere. Data were accessible, the workstations were set up properly, Internet-based projection facilities made presentations easy, and best of all the software (SolarSoft, including now the new mapping package written by Dominic Zarro), worked brilliantly. For many of the participants this was the first time to have a chance to do proper overlays of SOHO data, including MDI magnetograms crucial to the connectivity, with Yohkoh and other images. SolarSoft should be the standard environment for future data analysis work. Work continues on the Web presentation of the third SOHO-Yohkoh CDAW (Coordinated Data Analysis Workshop), with several people cleaning up loose ends. This CDAW really brought us to a good position with respect to "Web reporting" as an alternative to yet another conference proceedings. Canfield worked with Sean Sandborgh and Alex Pevtsov on the chirality of large-scale structures in SXT images; Sean presented the paper in congress -- to, among other people, both MT senators. He also worked with Hugh Hudson on sigmoidal structures in SXT data in 1997. Metcalf continued SXT/HXT data analysis of a number of flares looking for signatures of coronal trapping in flares, much like we observed in the 1992 Jan 13 flare. Preliminary results show trapping similar to the 1992 Jan 13 flare in *all* events. Page 3 << 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 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 March were 77114 accesses and 2564 Mbytes transferred. << Yohkoh Operations and Health >> The recovery from the filter rupture of Jan. 24 is almost complete. We continue to make terminator images to help compensate for the extra light; we now have terminators in four different filter configurations. Yohkoh and the SXT continue to function very well. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT Line Sync 11-Apr-98 Pass 5: 980411-0722 recovered in pass 1 on 13-Apr-98. SXT Bit Map Error 21-Apr-98 Pass 2: 980421-0104 recovered in the same pass. SXT Bit Map Error 24-Apr-98 Pass 5: 980424-0413 recovered in the same pass. SXT Bit Map Error 29-Apr-98 Pass 4: 980429-0205 recovered in the same pass. Page 4 << Data Flow >> Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jan-96 351786 152207 1459089 360329 1819418 728135 28.46 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 7515 2723 31952 1536 33488 14521 30.25 Jul-96 5954 1995 29886 4769 34655 12427 26.39 Aug-96 7214 3010 21187 1607 22794 9887 30.25 Sep-96 6904 2618 29906 303 30209 12663 29.54 Oct-96 7405 2853 16463 1842 18305 8034 30.50 Nov-96 7001 2296 24292 5395 29687 9340 23.93 Dec-96 7144 2643 25331 2087 27418 10412 27.52 Jan-97 7186 2747 21126 1257 22383 9915 30.70 Feb-97 6016 2034 22097 1072 23169 8961 27.89 Mar-97 7152 1300 26991 1209 28200 6394 18.48 Apr-97 6018 1055 23639 3890 27529 5349 16.27 May-97 7703 1455 29574 3783 33357 7121 17.59 Jun-97 7671 1557 25649 1396 27045 8045 22.93 Jul-97 8614 1385 32503 431 32934 6559 16.61 Aug-97 7316 987 23136 3519 26655 4990 15.77 Sep-97 7051 1479 33646 9596 43242 8887 17.05 Oct-97 7023 1134 26813 1827 28640 6043 17.42 Nov-97 6691 1376 26297 15306 41603 7131 14.63 Dec-97 6806 1013 28472 2136 30608 5263 14.67 Jan-98 5715 1803 23479 3232 26711 9918 27.08 Feb-98 6606 1644 25257 3606 28863 8989 23.75 Mar-98 6043 2056 23029 10399 33428 10939 24.66 Apr-98 2430 446 8860 3101 11961 2684 18.33 May-98 0 0 0 0 0 0 NaNQ Total 534169 203816 2161208 447738 2608946 976869 27.24 Number of Full Frame Images Received: 534169 Number of Observing Region Images Received: 2608946 Total: 3143115 Approximate Number of Shutter Moves/CCD Readouts: 5475174 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 5 << 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 (%) 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 52.58 827.5 165676 12393 19.6 N/A Sep-96 52.47 823.3 162784 12350 20.0 N/A Oct-96 52.21 813.8 157689 12047 22.5 / 2 21.3 N/A Nov-96 52.45 822.9 161683 12534 21.9 N/A Dec-96 53.08 846.2 171224 13860 22.9 N/A Jan-97 52.35 818.9 164785 11354 23.8 / 7 23.3 N/A Feb-97 51.95 803.9 159426 10346 21.1 N/A Mar-97 55.99 955.6 158428 12190 21.2 N/A Apr-97 53.14 848.4 176207 13265 20.8 N/A May-97 52.96 841.7 172052 13094 20.7 N/A Jun-97 53.71 869.8 182715 14910 19.8 N/A Jul-97 54.44 897.3 184518 20173 22.5 / 2 21.1 N/A Aug-97 54.06 883.1 188485 15549 20.1 N/A Sep-97 54.77 909.7 196501 17757 21.0 N/A Oct-97 54.85 912.8 198157 17857 21.5 N/A Nov-97 55.17 924.8 202153 18993 22.5 / 2 23.1 N/A Dec-97 55.51 937.6 206194 20219 21.9 N/A Jan-98 56.06 958.0 212189 22121 23.9 N/A Feb-98 55.94 953.7 209254 22122 23.8 / 2 22.6 N/A Mar-98 56.29 966.6 213519 23249 21.8 N/A Apr-98 56.46 973.0 215162 24040 21.1 N/A May-98 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 6 << Personnel Travel >> SXT Foreign Travel between 1-APR-98 and 30-APR-98 CANFIELD 18-APR-98 30-APR-98 13 (total of 13 days) DAVEY 1-APR-98 * 10-APR-98 10 (total of 10 days) FREELAND 1-APR-98 * 11-APR-98 11 (total of 11 days) HUDSON 1-APR-98 * 26-APR-98 26 (total of 26 days) MCKENZIE 27-APR-98 30-APR-98 * 4 (total of 4 days) NITTA 1-APR-98 * 26-APR-98 26 (total of 26 days) ---------------------------------------------------------------- Grand Total of 90 days for 6 people NOTE: The "*" signifies travel that actually ends after 30-APR-98 SXT Foreign Travel between 1-MAY-98 and 31-MAY-98 HUDSON 10-MAY-98 20-MAY-98 11 31-MAY-98 31-MAY-98 * 1 (total of 12 days) MCKENZIE 1-MAY-98 * 31-MAY-98 * 31 (total of 31 days) SHIRTS 8-MAY-98 15-MAY-98 8 (total of 8 days) SLATER 8-MAY-98 15-MAY-98 8 (total of 8 days) ---------------------------------------------------------------- Grand Total of 59 days for 4 people NOTE: The "*" signifies travel that actually ends after 31-MAY-98 Respectfully submitted, Thomas R. Metcalf Frank Friedlaender Page 7 ------------------------------------------------------------------------------- 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 May 1998 April 1998 |------------------------------- | 6. PERFORMING ORG | CODE: O/H1-12 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- T. R. Metcalf | TION REPORT NO: F. M. Friedlaender | |------------------------------- -----------------------------------------------|10. WORK UNIT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS | Lockheed Martin Missiles and Space |------------------------------- Advanced Technology Center, O/H1-12, B/252 |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 Contact: John Owens | of April 1998 |------------------------------- |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 | 7 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office