Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for June 1999) 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 All of the programmatic and financial aspects of the program are continuing in a nominal manner. The RFP for the continuation of operations and data analysis is expected late in July. SOLAR ACTIVITY Early June saw many active regions, including several sigmoidal structures which, as expected, erupted. Through mid-June, solar activity remained moderate, although there were about 10 active regions on the disk. There were over twenty C-class flares, but only one M-class event (M1.8). In late June, activity remained moderate with many active regions (13 on June 17), but little flare activity. Judging from the level of Type II bursts, CME's, and flickering X-rays around the North limb, the invisible hemisphere likely had a high level of activity. The activity in AR8585, the target of the first Max Millennium campaign, was disappointingly low. SXT observed two C-class flares on 19 June and two C- class and one M-class flare on 20 June. On June 26, there were 21 active regions on the disk. The ratio of C/M flares was 54/2 through June 19, implying a steeper distribution function than the canonical ratio of 10/1. This is probably explained by the statistics of small numbers, but it is unusual to have so many C-class flares with so few M-class flares. Page 2 CAMPAIGNS This continues to be a busy season for observing campaigns, owing partly to the activity at the Swedish Vacuum Solar Telescope (La Palma). This has included a long series of observations (SOHO JOP 183) aiming at moss, for which it appears that the SXT data (high temperature, high pressure) will play a key role in the interpretation of the newly discovered transition region structure. The correspondents have been Tom Berger and Bart Depontieu from LMSAL. SXT also supported Jing Li's UVCS campaign by doing an offpoint. This is the first systematic offpoint observation we have attempted in a long time and we have learned a great deal about the key factor: stray- light corrections. SXT supported the first Max Millennium campaign, a practice run for HESSI, together with TRACE, SOHO, and 27 ground based observatories on 6 continents. SXT followed the target region, AR8585, from 15 June through 18 June. AR8585 was also the target for the campaign, "Dynamics and Structure of Large Sunspots" (SOHO JOP 188), with participation from SXT, CDS, TRACE, MDI, and La Palma. On June 24, SXT supported the SERTS rocket flight. The flight took place on 24 June from 17:00 to 17:10 and 5 spectra were obtained with the slit across the active regions in the NE quadrant. SXT took 2 series of 2X2 PFI's of the target region in 5 filters and one darkcal PFI, as well as 2 FFI's. Other participants were CDS, EIT, MDI, Kitt Peak, Sac Peak, and Big Bear. SCIENCE Acton worked with Ahilleas Maurellis at the FOM-Institute for Atomic and Molecular Physics in Amsterdam on modeling X-ray emission from Jupiter. They need the solar x-ray input which Acton is providing. He wrote a program that converts SXT full-disk fluxes to radiance in a spectral band. It makes use of 2-filter color temperatures for a spectral distribution. This feature greatly increases the accuracy of the result according to Acton, Weston and Bruner (to appear in JGR-Space Physics). McKenzie continued work on the observations of flow fields above LDE flare arcades. He compared SXT images to coincident (spatial and temporal) MLSO H-alpha images, and found no evidence for H-alpha blobs in the region above the arcades where X-ray voids are observed. Examination of EIT & TRACE images yields the same result: EUV sees the arcade, but doesn't seem to reveal anything above the arcade. A comparison of the measured downflow velocities and the times/locations of the velocity measurements may place some constraints on the necessary rise speed of the CME material, if the downflow is purely gravitationally motivated; however, it is unlikely this will pan out as a useful constraint for determining the force which accelerates the X-ray voids. A beautiful eruption of a polar crown filament in the the SE quadrant of the Solar disk was seen by several ground based and space based observatories on 13 June. In just a few hours, most of the filament disappeared. EIT saw the whole eastern part of the structure appear to be ripping into space, while the Page 3 western part was still firmly on the Sun, as the Meudon observations also show. The LASCO C2 coronagraph observed the ejection two hours after the EIT image, on 14 June 1999 at 15:06 UT. The filament, or at least the lasso-like magnetic structure coming from that same region, reached a distance of 6 Solar radii above the surface, just over 4 million km. SXT observed a cusped loop stretching out after the erupted filament followed by a whole arcade of loops. While the filament eruption and CME continued, the arcade slowly grew larger and higher in the SXT images. An interesting feature, best seen in the full-size images, was the magnetic loop linking the arcade with a small active region near the Solar equator. The sequence of events agrees beautifully with one of the standard theories of Solar flares, the so-called CSHKP model. A key element of this model is that the eruption of the filament forces reconnection in a current sheet below it, leading to the formation and energization of an arcade of postflare loops: the arcade that SXT observes in Soft X-rays. An open question in this model is still the exact relation (causal and temporal) between the filament eruption and the accompanying CME. Rarely has such a pure and large-scale specimen of this type of event been observed. And only since very recently, with Yohkoh and SOHO together in orbit, has it been possible to cover these eruptions in so many different wavelengths simultaneously -- clearly, a prerequisite for putting together the global picture. 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 June were 80330 accesses and 4906 Mbytes transferred. 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 SHUTTR Error 24-June-99 Pass 1: 990624-0824 Recovered in Pass 4 Page 4 DATA FLOW Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Apr-97 454500 187481 1854493 389406 2243899 890300 28.26 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 6537 1103 22656 8087 30743 6339 17.09 May-98 7569 1838 28292 19018 47310 9868 17.26 Jun-98 6463 1638 24990 5618 30608 9051 22.82 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 3330 1053 24258 8006 32264 9995 23.65 Jun-99 0 0 0 0 0 0 -NaN Jul-99 0 0 0 0 0 0 -NaN Total 618769 226452 2495239 610342 3105581 1106136 26.26 Number of Full Frame Images Received: 618769 Number of Observing Region Images Received: 3105581 Total: 3724350 Approximate Number of Shutter Moves/CCD Readouts: 6395695 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 (%) 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 56.44 972.1 214676 23890 20.8 N/A May-98 56.90 989.4 215651 26905 21.4 N/A Jun-98 57.11 997.5 216285 28223 20.1 N/A 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 22.5 N/A Jun-99 59.40 1083.0 230091 42440 0.0 N/A Jul-99 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-JUN-99 and 30-JUN-99 HANDY 26-JUN-99 30-JUN-99 * 5 (total of 5 days) HUDSON 2-JUN-99 30-JUN-99 * 29 (total of 29 days) MARTENS 5-JUN-99 30-JUN-99 * 26 (total of 26 days) SLATER 1-JUN-99 * 30-JUN-99 * 30 (total of 30 days) ---------------------------------------------------------------- Grand Total of 90 days for 4 people NOTE: The "*" signifies travel that actually ends after 30-JUN-99 SXT Foreign Travel between 1-JUL-99 and 31-JUL-99 HANDY 1-JUL-99 * 31-JUL-99 31 (total of 31 days) HUDSON 1-JUL-99 * 31-JUL-99 * 31 (total of 31 days) MARTENS 1-JUL-99 * 2-JUL-99 2 (total of 2 days) SHIRTS 15-JUL-99 31-JUL-99 * 17 (total of 17 days) SLATER 1-JUL-99 * 2-JUL-99 2 (total of 2 days) ---------------------------------------------------------------- Grand Total of 83 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-JUL-99 Respectfully submitted, Thomas R. Metcalf Frank M. 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 July 1999 June 1999 |------------------------------- | 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 - 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: Larry Hill | of June 1999 |------------------------------- |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