Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-00119) (for February 2001) 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 Martin, 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 Martin Solar and Astrophysics 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 There were no major programmatic activities in the month of February.The instrument and staff are both in good working order and continue to provide superior scientific data to the solar community. SOLAR ACTIVITY Activity has been amazingly low considering the phase of the solar cycle. Only one M-class flare (almost exactly zero UT February 3) occurred during the entire month. As usual in cases like this, we hope that the Sun is saving its fireworks for the HESSI launch. Also we note that the doldrums extend globally (ie, last longer than 1/2 rotation) even though there have been one or two LASCO reports of "backsided" halo CMEs. There was a smattering of C class flares. CAMPAIGNS We carried out no cooperative observing programs during this interval, but have a target-of-opportunity (TOO) search for sigmoid structures under way since Dec. 9. SCIENCE Acton concentrated on attempts to characterize the X-ray scattering properties of the SXT by analysis of starburst images. There is a good selection of starbursts to study but, of course, none of them are perfect for the purpose ... many will have to be studied to get definitive results for all filters, all leak eras, and all pointings. Thank goodness that we continued to make FFIs during SAA times or our Page 2 starburst database would be very small. Aschwanden used soft X-ray and EUV data from space observations with Yohkoh, SoHO, and TRACE to establish three important observational constraints for coronal heating models: (1) Coronal loops have an overdensity that can only be supplied by upflows of heated chromospheric plasma, (2) chromospheric upflows have been observed in a large number of coronal loops, and (3) the coronal heating function has been localized in the lower corona within a height range of approximately 10-20 Mm above the photosphere. Aschwanden has compared a comprehensive set of theoretical models of coronal heating to check whether they can satisfy the above observational constraints. He finds that conventional DC and AC coronal heating models that consider coronal loops as homogeneous flux tubes (in density and temperature), detached from the transition region, do not predict these observed effects, while refined models that include gravity and chromospheric models can reproduce the observed effects. Alternatively, most of the magnetic reconnection models previously used for flares, can reproduce the observed effects, because heating of the chromospheric plasma at the loop footpoints is involved with subsequent chromospheric evaporation as in flares. Therefore, coronal magnetic reconnection processes that work with lower heating efficiency than in flares, as well as chromospheric and photospheric reconnection processes should be considered as serious candidates for coronal heating models. The main conclusion is that the coronal heating problem cannot be solved without including dynamic processes (and related heating effects) in the chromosphere and transition region zone. Canfield worked with postdoc Bob Leamon on the interplanetary signatures of eruptions that occurred in Yohkoh X-ray sigmoids. The preliminary finding is that leading polarity properties of the clouds tend not to take on the polarity of the large-scale dipole, unlike magnetic clouds as a whole. McKenzie continued to work on the deconvolution of the SXT scattering wings. In summary, deconvolution can be made to work, with careful choice of the point spread function. He found that the scattering wings assume approximately 7% of the total signal. He also found that a PSF comprising a Moffat-function core plus scattering wings leads to a deconvolution that badly overcorrects, whereas a PSF comprising a delta-function core plus scattering wings leads to a much better deconvolution. PUBLICATIONS Submitted: Accepted: Watanabe, T., Sterling, A., Hudson, H., and Harra, L., "Energetics of an active region observed from helium-like sulphur lines", accepted by Solar Physics, Feb. 2001. Page 3 Nitta, N. V., Sato, J., and Hudson, H. S., "The physical nature of the loop-top X-ray sources in the gradual phase of solar flares, accepted by ApJ, Feb. 2001. Published: 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 LMSAL SXT WWW homepage (http://www.lmsal.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. he WEB access statistics in February were 198781 accesses and 8394 Mbytes transferred for the SXT website and 211954 accesses and 4402 Mbytes transferred for the YPOP website. YOHKOH OPERATIONS AND HEALTH Yohkoh and the SXT continue to function very well. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT FIL Error 01-Feb-01 Pass 5: 010301-0721 Recovered in the second pass on Feb 2. Page 4 DATA FLOW Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Dec-98 590694 218834 2370258 558385 2928643 1058034 26.34 Jan-99 5494 1825 20087 17620 37707 9622 20.33 Feb-99 5729 1525 30802 9798 40600 10630 20.75 Mar-99 6807 1844 24721 12354 37075 10064 21.35 Apr-99 6715 1371 25113 4179 29292 7791 21.01 May-99 6459 1807 35467 12092 47559 13757 22.44 Jun-99 6217 1915 23542 13051 36593 10086 21.61 Jul-99 5591 1745 20409 25747 46156 9670 17.32 Aug-99 6827 2503 21725 23361 45086 11844 20.80 Sep-99 5768 2011 21890 3434 25324 10846 29.99 Oct-99 5768 2308 22994 10487 33481 11517 25.59 Nov-99 7552 3425 20754 18772 39526 11974 23.25 Dec-99 7488 2791 22047 5354 27401 10663 28.01 Jan-00 5426 1736 19802 4040 23842 8958 27.31 Feb-00 6533 2052 21801 7017 28818 8982 23.76 Mar-00 6447 2007 22692 21914 44606 11192 20.06 Apr-00 6412 2100 31195 7214 38409 13438 25.92 May-00 6995 1556 28175 14961 43136 8967 17.21 Jun-00 7043 1722 24413 16369 40782 8690 17.57 Jul-00 6674 1920 23505 31739 55244 10235 15.63 Aug-00 9623 1996 20925 1197 22122 6577 22.92 Sep-00 8835 2240 22233 5764 27997 8307 22.88 Oct-00 6348 1524 23309 6629 29938 7916 20.91 Nov-00 6525 1639 20087 10318 30405 6972 18.65 Dec-00 6585 1918 20718 5422 26140 8071 23.59 Jan-01 5610 1231 20469 3161 23630 7317 23.64 Feb-01 720 229 2703 161 2864 1063 27.07 Total 756885 267774 2961836 850540 3812376 1303183 25.47 Number of Full Frame Images Received: 756885 Number of Observing Region Images Received: 3812376 Total: 4569261 Approximate Number of Shutter Moves/CCD Readouts: 7773630 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 (%) Jan-99 58.74 1058.6 227503 38238 23.1 N/A Feb-99 58.44 1047.4 224002 36198 23.2 N/A Mar-99 59.26 1078.1 227900 43051 21.7 N/A Apr-99 58.82 1061.4 225973 38963 23.8 / 1 21.4 N/A May-99 58.68 1056.4 225385 37726 21.6 N/A Jun-99 59.40 1083.0 230091 42440 22.0 N/A Jul-99 59.78 1097.5 231236 46337 23.8 / 1 20.6 N/A Aug-99 59.39 1083.0 229319 43067 21.7 N/A Sep-99 60.04 1107.3 231585 49084 21.8 N/A Oct-99 59.66 1092.9 229735 45263 22.8 N/A Nov-99 59.90 1102.0 231288 47102 23.0 N/A Dec-99 60.55 1126.3 233523 53920 22.5 / 2 25.3 N/A Jan-00 60.27 1115.9 233820 50214 23.4 N/A Feb-00 60.93 1140.6 235079 56836 23.8 N/A Mar-00 60.72 1132.8 234174 54661 22.9 N/A Apr-00 61.10 1147.0 235252 58348 22.2 N/A May-00 61.00 1143.1 234569 57445 21.2 N/A Jun-00 61.19 1150.3 235622 58946 22.8 N/A Jul-00 61.96 1179.3 238114 66905 19.3 N/A Aug-00 61.27 1153.4 236108 59965 56.9 / 2 21.7 N/A Sep-00 61.08 1146.2 235644 58449 22.1 N/A Oct-00 61.44 1159.5 237142 61667 23.1 N/A Nov-00 60.99 1142.7 235849 57271 24.2 N/A Dec-00 61.59 1165.2 237454 63656 23.8 / 2 21.8 N/A Jan-01 61.64 1167.3 238962 62922 22.2 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 6 PERSONNEL TRAVEL SXT Foreign Travel between 1-FEB-01 and 28-FEB-01 BARTUS 1-FEB-01 * 28-FEB-01 * 28 (total of 28 days) HUDSON 5-FEB-01 16-FEB-01 12 28-FEB-01 28-FEB-01 * 1 (total of 13 days) NITTA 18-FEB-01 28-FEB-01 * 11 (total of 11 days) TAKEDA 1-FEB-01 * 28-FEB-01 * 28 (total of 28 days) ---------------------------------------------------------------- Grand Total of 80 days for 4 people NOTE: The "*" signifies travel that actually ends after 28-FEB-01 SXT Foreign Travel between 1-MAR-01 and 31-MAR-01 BARTUS 1-MAR-01 * 31-MAR-01 * 31 (total of 31 days) HUDSON 1-MAR-01 * 14-MAR-01 14 (total of 14 days) NITTA 1-MAR-01 * 16-MAR-01 16 (total of 16 days) TAKEDA 1-MAR-01 * 31-MAR-01 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 92 days for 4 people NOTE: The "*" signifies travel that actually ends after 31-MAR-01 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 March 2001 February 2001 |------------------------------- | 6. PERFORMING ORG | CODE: O/L9-41 -----------------------------------------------|------------------------------- 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/L9-41, B/252 |11. CONTRACT OR GRANT NO. 3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 00119 -----------------------------------------------|------------------------------- 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: Larry Hill | of February 2001 |------------------------------- |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 | ------------------------|------------------------|-----------------|-----------