Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for the month of June, 1992) OVERVIEW 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 from Kagoshima Space Center (KSC) in Japan, and renamed Yohkoh. The purpose of this mission is to study high energy phenomena in solar flares. 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 by Lockheed in cooperation with the National Astronomical Observatory of Japan, and the Institute for Astronomy of the University of Tokyo. MAJOR ACTIVITIES IN THE MONTH << Solar Activity and Observation Planning >> The SXT and the other instruments on Yohkoh continue to work very well. During the past month there were no SXT operational problems. The solar activity was fairly low. Last week, the SXT tracked the passage of NOAO AR 7186 across the disk. The region produced several small flares, including an M1.5/1B on 8 June at 08:43 UT, which was also observed by the Lockheed observers at La Palma Swedish Observatory, using the tunable filter. This flare appears to have occurred at the site of two interacting loops. This configuration has now been observed on several occasions. On 8 June, one loop appeared to have a potential geometry, crossing the neutral line, whereas the intersecting loop appeared not to be a potential geometry, but was somewhat sheared, following the neutral line. Filament disappearances were observed on 11 June (10:57 UT) and 12 June (11:03 UT). The SXT continues to observe a variety of coronal features, including jets, post-flare loop expansions, bright points, emerging flux regions, etc. << Data Analysis Software >> A variety of new software has been made available over the past month. Some of the contributions were directed at making ground based data available to the Yohkoh team members. Software is now in place to automatically copy the GOES event listings, NOAA active region listings, and h-Alpha and magnetograms from the SELSIS computer and the Big Bear institution. These files are copied every day to ISAS and plans are being made to distribute the data to the Yohkoh users on the Yohkoh distribution tapes. Page 2 << Instrument Operations and Health >> The SXT TEC was turned off between 8-Jun to 9-Jun to perform a "bakeout" of the CCD. Recent diffuser images have indicated that there was again a build up of some kind of ice or material on the surface of the CCD. On this occasion (unlike the time in May), the thermal strap heater was not turned on. The data is currently being analyzed. However, a small improvement in the transmission through the Aspect Telescope narrow band filter has been observed. << Data Flow >> There have been no problems staying up with the flow of Yohkoh data, and tapes arrive at the remote institutions within 1-2 weeks after the data is taken. The old data is still to be re-reformatted in order to take advantage of more recent modifications to the data structures and content. << Problems >> The aspect telescope degradation continues, but has established that the decay is very exponential, so we expect that we can continue to use the telescope for several years. << Papers and Conferences >> Dr. James Lemen attended the G. S. Vaiana Memorial Symposium in Palermo, Sicily, in mid-June which was arranged to mark the untimely death of Dr. Giuseppe Vaiana, who was the directory of the Palermo Observatory, and the 200th anniversary of the observatory. Dr. Lemen presented an overview of SXT/Yohkoh results in an invited talk. Two other invited talks describing SXT data where made my Drs. Saku Tsuneta (NAOJ) and Prof. Y. Uchida (Tokyo University). The majority of the meeting's participants were from the cool stars community, and they showed considerable interest in the SXT results. Video presentations were made as part of the talks and these were popular enough to warrant a second showing later in the meeting. The Yohkoh Team presented a total of 18 papers detailing the initial results from the mission at the recent AAS-SPD meeting in Columbus, Ohio. There were three sessions that featured Yohkoh results. They were all well attended. Lockheed made 200 VHS videos available that were handed out free to the attendees. These were enthusiastically received and we are still getting requests for more. A press conference was held which featured a presentation of SXT results by Dr. Marilyn Bruner during which the video was presented to them. The normally jaded press corps reacted with surprising interest. In fact they interviewed Dr. Bruner and Dr. Keith Strong for several hours after the press conference was over. These discussions should result in several popular and feature articles. Page 3 << Personnel Travel >> The staffing at ISAS for Jun-92 was: ACTON 1-JUN-92 * 10-JUN-92 10 (total of 10 days) HUDSON 1-JUN-92 * 3-JUN-92 3 19-JUN-92 30-JUN-92 * 12 (total of 15 days) LEMEN 4-JUN-92 20-JUN-92 17 28-JUN-92 30-JUN-92 * 3 (total of 20 days) LINFORD 1-JUN-92 * 3-JUN-92 3 11-JUN-92 30-JUN-92 * 20 (total of 23 days) MORRISON 1-JUN-92 * 10-JUN-92 10 (total of 10 days) NITTA 1-JUN-92 * 6-JUN-92 6 21-JUN-92 30-JUN-92 * 10 (total of 16 days) MARTENS 4-JUN-92 30-JUN-92 * 27 (total of 27 days) The planned staffing at ISAS for Jul-92 is: FREELAND 15-JUL-92 31-JUL-92 * 17 (total of 17 days) HUDSON 1-JUL-92 * 5-JUL-92 5 13-JUL-92 31-JUL-92 * 19 (total of 24 days) LEMEN 1-JUL-92 * 17-JUL-92 17 28-JUL-92 31-JUL-92 * 4 (total of 21 days) LINFORD 1-JUL-92 * 10-JUL-92 10 (total of 10 days) MORRISON 15-JUL-92 19-JUL-92 5 (total of 5 days) NITTA 1-JUL-92 * 20-JUL-92 20 (total of 20 days) MARTENS 1-JUL-92 * 28-JUL-92 28 (total of 28 days) << Plans for July 1992 >> *. Continue the Data Analysis and Reduction software development effort. *. Continue mission operations and data analysis at ISAS. Respectfully submitted, Mons D. Morrison Frank Friedlaender Page 4 -------------------------------------------------------------------------------- UNIVERSITY OF HAWAII ACTIVITY REPORT (DR. R. CANFIELD) MAJOR ACTIVITIES FOR THE MONTHS OF MAY AND JUNE Our most important Solar-A activities during this period were Mees and Yohkoh operations, Yohkoh support, preparation of publications, presentation of papers at meetings, and the initial observations with our new Imaging Vector Magnetograph. Graduate student Litao Jiao replaced Jun Chen as Yohkoh research assistant in mid-June. Tom Metcalf spent the first two weeks of May at ISAS. Hudson served in various capacities in Yohkoh operations over this period, including SXT table management. Among the special experiments carried out were several high time resolution studies, on behalf of persons interested in "microflares", "nanoflares", "transient loop brightenings", or other related phenomena. At least two good sets of data with time resolution to 8 sec were obtained. At Mees, Judd, Nitta and Koon served as duty observers, and Canfield, Wuelser, Metcalf, and Leka as Yohkoh duty scientists. This period was characterized by good weather at Mees and fairly low activity on the sun. The Mees instruments functioned well through the campaigns on AR 7205 and 7216. The first IVM magnetograms were obtained on these regions. Kiernan got the Yohkoh software going for SPAM; its Yohkoh database is now complete through the end of 1991. Metcalf worked with Kiernan on determining Yohkoh pointing for the SPAM database and specifying relevant searches to be programmed. He and Canfield worked with Kiernan to define desirable multi-database searches. Hudson, Wuelser, Mickey, Metcalf and Canfield presented papers at the AAS meeting in June. Canfield organized the Yohkoh session at the AAS meeting. Canfield finished the PASJ first-round paper on Mees/Yohkoh observations of the November 15th flare. Hudson finished the initial white-light flare paper for the same volume. All UH staff participated in one or more of these PASJ papers. Canfield and Leka worked on a manuscript for Ap.J. on the work previously described at Yohkoh meetings, on the relationship between H-alpha flare processes, magnetic fields, and currents. Metcalf continued analyzing data from AR6952 and wrote IDL programs to generate co-aligned movies from a series of PFI and FFI data files. He used this code to analyze AR6952 over the period Dec 6 to Dec 9, 1991. He also worked on the relationship between the vertical currents and the HXT images in the Nov 15 flare. Hudson worked on X-ray flare observation and active region observations, emphasizing data obtained during Mees observations. Another important topic, also presented at Columbus, has to do with the soft X-ray structures observed in LDE/GRF events. The Page 5 SXT data on such events is superb and clearly reveals morphological differences from the impulsive flares. The BATSE instrument on Compton/GRO shows long-duration hard X-ray bursts in such events, however, so similar mechanisms of particle acceleration and energy transfer appear to be operating despite the geometrical differences. Mickey, Metcalf, Leka, and the engineering staff succeeded in producing the first high-quality vector magnetograms with the IVM. They was able to improve the IVM spectral resolution significantly by electrically isolating the etalon. The resolution is now about 8 pm, which appears to be adequate for deducing magnetic fields. With better spectra, and a change from the 6301.5 line to the 6302.5 line, it became clear that there was an instrumental problem which was causing crosstalk between circular and linear polarization. They finally tracked this down to the small exit window of the telescope, removed it, and the crosstalk is gone. During the last week of June, Mickey and Leka obtained high quality magnetograms of AR7205 and AR7216, to our great pleasure. The area observed is 4x3 arcminutes, the spatial resolution is about 3 arcseconds, the line of sight field is measured to about 20 gauss and the transverse to about 200 gauss. The improvement over the Polarimeter is indeed striking. Metcalf essentially completed the algorithm which computes the magnetic field from IVM data. PLANS FOR JULY AND AUGUST Mickey, Leka, and the Mees observers will begin using the IVM, in addition to the Stokes and MCCD, but only during appropriate campaigns, until procedures are streamlined and the observers are trained in the use of the instrument. An important early task is to compare the IVM with the very well-characterized Stokes polarimeter, with regard to both hardware and analysis software. Metcalf plans to wrap up his study of currents and X-ray structures in AR6952. The final step is to separate the SXT data into slowly-varying and flaring components. Metcalf and Jiao plan to work on the height dependence of the magnetic field in the photosphere and chromosphere. Canfield and Leka will finish up the papers on H-alpha flares, magnetic fields, and currents. Hudson will continue his work on flares and active regions, including the preparation of a paper on LDE/GRF events that combines Yohkoh and Compton/GRO data. His other scientific efforts include participation in studies of microflares and of coronal structure. Hudson's support functions will include normal operations duties, plus work on coalignment between HXT and SXT, and jitter stabilization of the SXT images. Wuelser, Canfield, and Metcalf will work on the Nov 15th and October 24th X flares. Page 6 -------------------------------------------------------------------------------- UNIVERSITY OF CALIFORNIA AT BERKELEY (DR.KANE) As mentioned in the previous report, the UCB team presented two Yohkoh-related papers at the ASJ meeting in Osaka from May 11-13 and also at the AAS/SPD meeting in Columbus Ohio, from June 7-11. The first paper, titled "Characteristics of Two Energetic Solar Flares Observed with Yohkoh", by Kane, McTiernan, Loran, Yoshimuri, Watanabe and Kosugi, is a discussion of the results gained from the study of flares on 2-NOV-91 and 15-Nov-91, using the Yohkoh SXT, HXT and WBS along with data from the GOES, Ulysses and PVO spacecraft. The second, titled "Temperature Structure of Solar Flares observed by the Soft X-ray Telescope on Yohkoh", by McTiernan, Kane, Loran, Lemen, Acton, Hara and Tsuneta, examines the spatial temperature variations in flare plasmas, using filter ratios obtained by SXT, concentrating on the two flares mentioned above. These papers are now being prepared for publication. In addition to the work with WBS and SXT, we have been working on writing image synthesis software for the HXT, which can be used to obtain images directly using data from the reformatted data base. A preliminary version of the program, translated into IDL from T. Sakao's program MOVIE7, is complete, has been tested on data from the Nov. 15, 1991 flare, and gives the same results as the Fortran version. This program will be made available in the yohkoh software directory on the ISAS workstations tomorrow (July 7). A faster version of the program should be available shortly. Page 7 -------------------------------------------------------------------------------- STANFORD UNIVERSITY (DR. P. STURROCK) Our main Yohkoh-related activities during this reporting period are as follows. Jim Klimchuk, Taeil Bai, and George Roumeliotis attended the American Astronomical Society Meeting held June 8-11 in Columbus, Ohio. Klimchuk gave a talk entitled "Thickness Variations Along Coronal Loops Observed By Yohkoh" (coauthored by Lemen, Feldman, Uchida, and Kluge), Bai gave a talk entitled "Apparent Variability of the Occurrence Frequency of Solar Flares as a Function of Peak Hard X- ray Flux," and Roumeliotis presented a poster entitled "Numerical Investigation of a Proposed Mechanism for Coronal Mass Ejections." Klimchuk visited the High Altitude Observatory in Boulder, CO on June 24-26 to collaborate with David Sime, Director of the Mauna Loa Solar Observatory. The primary objective was to examine Mark III Coronagraph images of cornal mass ejections (CMEs). These data are now being compared with SXT data to determine the correspondence between white light (polarization brightness) and soft X-ray events. The eventual goal is to understand the early stages of evolution of CMEs and the relationship between CMEs and solar flares. Undergraduate Kevin Kluge is collaborating on this project. Roumeliotis has begun to consider the maximum entropy method of image enhancement and has selected candidate images for application of the method. We will continue to work on these projects over the next two months. In addition, Klimchuk will continue his study of thickness variations along coronal loops (with the colleagues listed above), and Sturrock, Bai, and Porter will begin to examine the SXT data. Page 8 -------------------------------------------------------------------------------- SOLAR PHYSICS RESEARCH CORPORATION (KAREN L. HARVEY) Activity these last two months has focussed on several areas: (1) Continuation of compiling a bibliography on X-ray bright points and associated activity. (2) Compilation of a bibliography of SXT/Yohkoh papers published. Several of the Yohkoh scientists have sent lists of the papers they are aware of or have written as part of this project. At this time, the SXT bibliography will consist of three lists: (1) papers published in referred journals, (2) papers presented at scientific meetings (listed by meeting), and (3) papers published in general science publications. (3) Assisted in the preparation of three papers for PASP: (1) Observations of the Variability of Coronal Bright Points: authors - K. Strong, K. Harvey, T. Hirayama, N. Nitta, T. Shimizu, and S. Tsuneta. (2) Simultaneous Observations of Coronal Bright Points in X-ray and Radio Wavelengths: authors - N. Nitta, T. S. Bastian, M. J. Aschwanden, K. L. Harvey, and K. T. Strong. (3) Global Restructuring of the Coronal Magnetic Fields observed with Yohkoh Soft X-ray Telescope: authors - S. Tsuneta, T. Takahashi, L. Acton, K. Harvey, Y. Ogawara. (4) Presentation of a paper entitled "X-ray Bright Point Flares Observed by Yohkoh" at the AAS/SPD meeting in Columbus, Ohio in June 1992. This paper discussed some of the results presented in the PASJ paper and additional events for which simultaneous magnetograms have been obtained in the last few months. Page 9 -------------------------------------------------------------------------------- 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 | July 10, 1992 June, 1992 |-------------------------------- | 6. PERFORMING ORGANIZATION | CODE: O/91-30 -----------------------------------------------|-------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- M. D. Morrison | 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 - 37334 -----------------------------------------------|-------------------------------- 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 Jan, 1992 |-------------------------------- |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 | 9 | ------------------------|------------------------|-----------------|------------ For sale by: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-0001 <<< END >>> Monday, Jul 13, 1992 7:20 PM PDT