Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-00119) (for August 2000) 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 Activities on the new contract are progressing well. All of the Co-Is are on board and continuing in their scientific endeavors. Jim Lemen and Frank Friedlaender visited with Chuck Holmes and Bill Wagner at NASA HQ and discussed the status of SXT, its future and the upcoming Senior Review in 2001. SOLAR ACTIVITY Solar activity was astonishingly low in August, although we have had 11 X-class flares thus far this year. The July 14 event, the biggest of this cycle, has attracted a lot of attention and will be the subject of a special session at the AGU meeting in December. Of the two M-class flares during early August, one chose to occur during one of our infrequent bakeouts, and we did not obtain any observations of it. A M1.9 flare occurred on 8-AUG (peak time: 11:15), and a M1.1 flare occurred on 12-AUG (peak time: 09:56). In the latter half of August, solar activity continued to be very low in terms of flare activity, although the corona continues to show us nice things. The August 25 M-class flare, just at the end of the Max Millennium campaign #10, turned out to be quite wonderful - coronal oscillations, ejecta, "knottiness", and a Type IV radio burst. CAMPAIGNS Yohkoh and SXT supported Max Millennium Campaign #10. This campaign aims to observe flare-related oscillations in the corona and photosphere using three satellite-borne instruments; TRACE, Yohkoh/SXT and SoHO/MDI. Page 2 SCIENCE We have been experimenting with both the FFI and the PFI flare-mode observing sequences. During August we obtained seven days of "RAPID" FFIs, which means sets of long-exposure Quarter-resolution images yielding a 32-second sampling interval. Our hope with this is to catch global waves related to EIT waves, Type II exciters, or Moreton waves. To do this the flare threshold has remained at its higher level, about C6. Thus far this mode has been disappointing, because of the low activity. For flare mode, we have for the first time begun to obtain 2x2 flare-mode images. At present the flare table has two entries, one normal AEC exposure and one overexposed AEC exposure (the McKenzie design). This results in a 16-sec sample interval and a 5 arc min field of view. The M-class flare of August 12 was observed in this mode and looked very good - nice wispy ejecta well-observed far from the flare core, but no wave. We plan to continue this until a few more flares have been observed. The "velocity filter" for global wave detection with this mode would be about v < 1500 km/s for about four glimpses of a wave originating at the flare core. On August 25, the Max Millennium Observing campaign #10 observed a limb flare with SXT, TRACE, and MDI. This flare was a "knotty flare" with structures too compact even for the 0.5-arcsec pixels of TRACE to resolve. Fletcher speculates that these brief, bright kernels of emission correspond to the footpoints of individual skinny coronal magnetic loops that guide high-energy electrons down into the chromosphere. Hints of this have come from timing analyses, but not yet directly from images. The TRACE movies show a puff-like ejection of material from the flare core and SXT also sees the ejection quite well. This implies an elevated temperature, and probably implies a broadly multi-thermal structure. SXT images show an extremely compact and energetic origin of the event, and the combined data set emphasizes how hard it is for us to see the dramatic range of flare phenomena in one glimpse. The Zurich radio group's "Phoenix" spectrometer caught a "drifting type IV decimetric event" during this flare - probably the first event of this type to be well-observed both at decimeter waves and soft X-rays. The radio spectrum evolved with time, with the emission drifting rapidly from high to low frequencies. This implies that the source moves from high to low densities, ie upwards, just as we simultaneously observe our "puff" ejection to move outwards from the solar surface. Because the radio observations explicitly determine the density of the source, if (as believed) the emission occurs at the plasma frequency, we can eliminate some of the ambiguity in interpreting the X-ray observations. For example, we constrain the elusive "filling factor" about which much argumentative heat gets dissipated. A first look suggests that the X-ray and radio data are mutually consistent with Page 3 reasonable temperatures (a few million K) and with large filling factor (ie, near unity). The main discovery in this event was a set of oscillating loops resulting from the flare - precisely the objective of the miraculously successful Max Millennium observing program. No doubt the ejection puff stimulated these oscillations, of which only a few other examples exist. Once the coronal magnetic structures oscillate, then the oscillation frequencies determine otherwise un-knowable properties of the corona, which we understand very well in some ways, but very poorly in others. PUBLICATIONS Submitted: Aschwanden,M.J., Schrijver,C.J., and Alexander,D. 2001 ApJ, URL="ftp://sag.lmsal.com/pub/aschwand/2000_dynamic.ps.gz" Modeling of coronal EUV loops observed with TRACE : I. Hydrostatic steady-state solutions with nonuniform heating" Aschwanden,M.J. and Acton,L.W.2001 ApJ, ... submitted URL="ftp://sag.lmsal.com/pub/aschwand/2000_acton.ps.gz" "Temperature tomography of the soft X-ray corona: measurements of electron densities, temperatures, and differential emission measure distributions above the limb" Accepted: Aschwanden,M.J., Nightingale,R.W., and Alexander,D.2000 ApJ 542, (Oct 10 issue), in press, URL="ftp://sag.lmsal.com/pub/aschwand/2000_serio.ps.gz" Evidence for nonuniform heating of coronal loops inferred from multi-thread modeling of TRACE data 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. The WEB access statistics in August were 114935 accesses and 6246 Mbytes transferred for the SXT website and 135228 accesses and 2994 Mbytes transferred for the YPOP website. Page 4 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: Bit Map Error 02-Aug-00 Pass 2: 000802-0721 Recovered in the same pass Sync 1 Error 11-Aug-00 Pass 2: 000811-0413 Recovered in pass 4 Bit Map Error 18-Aug-00 Pass 5: 000818-0618 Recovered in the same pass Bit Map Error 24-Aug-00 Pass 2: 000824-0103 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 Jun-98 552308 207949 2228286 477360 2705646 999443 26.72 Jul-98 6810 1892 27046 7357 34403 9970 22.47 Aug-98 5823 1960 22978 14126 37104 11167 23.13 Sep-98 6776 1432 21814 11626 33440 7753 18.82 Oct-98 6573 1901 23520 5198 28718 9220 24.30 Nov-98 6442 1695 25124 26948 52072 9920 16.00 Dec-98 5962 2005 21490 15770 37260 10561 22.08 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 6273 1750 22033 31645 53678 9469 15.00 Total 712238 256827 2829920 817794 3647714 1256194 25.62 Number of Full Frame Images Received: 712238 Number of Observing Region Images Received: 3647714 Total: 4359952 Approximate Number of Shutter Moves/CCD Readouts: 7396076 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 (%) Jul-98 57.01 993.7 215499 27493 21.4 N/A Aug-98 57.36 1006.7 217355 29544 20.9 N/A Sep-98 57.43 1009.5 218520 29683 20.9 N/A Oct-98 57.59 1015.3 220504 30221 21.3 N/A Nov-98 58.17 1037.0 223755 34614 22.5 / 2 23.4 N/A Dec-98 57.86 1025.5 221918 32420 23.8 N/A 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 19.1 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-AUG-00 and 31-AUG-00 FLETCHER 4-AUG-00 31-AUG-00 * 28 (total of 28 days) HUDSON 1-AUG-00 * 31-AUG-00 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 59 days for 2 people NOTE: The "*" signifies travel that actually ends after 31-AUG-00 SXT Foreign Travel between 1-SEP-00 and 30-SEP-00 FLETCHER 1-SEP-00 * 3-SEP-00 3 (total of 3 days) HANDY 24-SEP-00 30-SEP-00 * 7 (total of 7 days) HUDSON 1-SEP-00 * 30-SEP-00 * 30 (total of 30 days) NITTA 7-SEP-00 30-SEP-00 * 24 (total of 24 days) TAKEDA 1-SEP-00 30-SEP-00 * 30 (total of 30 days) ---------------------------------------------------------------- Grand Total of 94 days for 5 people NOTE: The "*" signifies travel that actually ends after 30-SEP-00 Respectfully submitted, Thomas R. Metcalf 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 September 2000 August 2000 |------------------------------- | 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 August 2000 |------------------------------- |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 | ------------------------|------------------------|-----------------|-----------