Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for the month of August, 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 At the end of August, Yohkoh celebrated its first anniversary since its successful launch on 31 August 1991. To mark the happy occasion, many of the spacecraft engineers were invited to ISAS for a party. It was a good opportunity to show an SXT video which nicely demonstrated how well Yohkoh had been performing. << Solar Activity and Observation Planning >> Solar activity remains relatively low, but many interesting solar phenomena can be seen in the on-going X-ray movie on the laser disk in Building D at ISAS. Most recently, NOAA region 7270 began to produce numerous C flares and an occasional M flare. A beautiful example of the formation of soft X-ray loops following the disappearance of an H-alpha filament can be seen in the north west on 18 August 1992. On 27 August 1992 the Yohkoh spacecraft was off-pointed 16 arc-min to the west during one orbit and then in the subsequent orbit was off-pointed 16 arc-min to the east so that the far corona could be observed with SXT. Since the solar X-ray luminosity was fairly low, we were able to make 1 min exposures. The far corona was similarly observed on 8 May 1992. The data show that the SXT can detect X-ray emission to very large heights above the solar limb (> 2000 arc-sec). The nature of the operations may make it too difficult to perform this kind of observation very often, but it we hope that future far corona observations can be made. One objective would be to try to monitor the heliospheric current sheet, as viewed at high temperatures, in cooperation with ground-based measurements. On 24 August the NRL HRTS rocket was successfully launched from White Sands Missile Range. In the days leading up to their launch, Dr Nariaki Nitta supplied daily SXT images via ftp to an NRL computer in order to assist the planning of the rocket observations. We have recently heard from Dr John Cook (NRL) that some of the film has been developed and that the data looks very good. We look forward to comparing SXT images with HRTS data. Page 2 << Data Analysis Software >> Synoptic maps of the 12 solar rotations which have occurred during the Yohkoh mission have been generated from desaturated SXT images. The software for extracting slices from the central meridian and +/-45 degree longitudes from all desaturated images has been included in the Yohkoh reformatter. Weekly SXT synoptic strip files have been generated for all mission weeks through early August. Display software has been written to allow construction of synoptic maps of arbitrary length in time or centered about an arbitrary Carrington longitude. A twelve frame movie of the twelve solar rotations since Yohkoh launch has been created. Software to extract coordinates of coronal hole boundaries from SXT images and differentially rotate these boundaries forward or backward in time to study feature evolution has been written. A preliminary application to the prominent dark channel which has been seen in SXT images for several solar rotations confirms that the rotation of this feature is nearly rigid (but not quite!) with a rotation rate of roughly 1.05 times the equatorial photospheric rotation rate given by Howard and Harvey (1970). << Instrument Operations and Health >> SXT continues to function very well and there were no operational problems during the past month. It is worth noting that in the past year the serial number counters have reached about 100,500 for the full frame images and nearly 500,000 for partial frame images. Since the partial frame images are often made up of multiple exposures (2x2 OG's), the true number of shutter operations in the past year was probably in excess of a million. Sam Freeland also notes that the last filter wheel error occurred in March before the SEU correcting code was implemented and it is likely that it was not a true error but only a symptom of the SEU itself. During the weekend of 5-Sep the TEC was turned off to warm up the CCD to about 0 C. The purpose of this was to evaporate whatever is condensing on the CCD front surface. The decision to do this was based on recent diffuser images. Although the data has not been fully analyzed, the narrow band filter image signal levels will probably increase by about five percent. The last time this was done was in early June, and it appears that it may be necessary to do this in the future every two to three months. << Data Flow >> RASM (Remote Access Schedule Mailbox) is a dial-in/dial-back system that JPL has installed for users of the DSN to obtain and request schedule information. In the past month we have begun to acquire the preliminary and final schedules with RASM using a modem connected to a one of the DECstations. We are currently exploring how we might improve the procedure of making long- term requests and for canceling unwanted passes from the preliminary schedule. For both of these tasks we currently rely on fax. Simplifying these tasks is desirable since the Yohkoh duty scientists currently spend about five to six hours per week on DSN issues alone. Page 3 << Problems >> The aspect telescope transmission continues to degrade at a familiar rate. At the beginning of August, the transmission was about 15% of the original value at launch. The CCD continues to perform well. The number of dark spikes have increased but these are not readily noticeable in short X-ray exposures. The increased dark current near the solar limbs will soon become more of a problem for the visible images and thus, may make flat fielding necessary for certain scientific objectives. << Papers and Conferences >> The autumn meeting of the Astrophysical Society of Japan (ASJ) is approaching. This year over 60 solar papers (nearly three times the previous maximum number) have been submitted and that many of these are based on Yohkoh observations. This is a partial indication of scientific activity that is based on Yohkoh data. The COSPAR meeting will take place in Washington, D.C. from September 1 to September 5, 1992. << Personnel Travel >> The SXT staffing at ISAS for August was: FREELAND 1-AUG-92 * 10-AUG-92 10 20-AUG-92 31-AUG-92 * 12 (total of 22 days) HUDSON 1-AUG-92 * 28-AUG-92 28 (total of 28 days) LEMEN 1-AUG-92 * 31-AUG-92 * 31 (total of 31 days) NITTA 7-AUG-92 31-AUG-92 * 25 (total of 25 days) MARTENS 1-AUG-92 * 31-AUG-92 * 31 (total of 31 days) The planned SXT staffing at ISAS for September is: ACTON 24-SEP-92 30-SEP-92 * 7 (total of 7 days) FREELAND 1-SEP-92 * 24-SEP-92 24 (total of 24 days) HUDSON 16-SEP-92 30-SEP-92 * 15 (total of 15 days) LEMEN 1-SEP-92 * 26-SEP-92 26 (total of 26 days) NITTA 1-SEP-92 * 10-SEP-92 10 26-SEP-92 30-SEP-92 * 5 (total of 15 days) MARTENS 1-SEP-92 * 30-SEP-92 * 30 (total of 30 days) WUELSER 9-SEP-92 30-SEP-92 * 22 (total of 22 days) Respectfully submitted, Mons D. Morrison Frank Friedlaender Page 4 -------------------------------------------------------------------------------- UNIVERSITY OF HAWAII ACTIVITY REPORT (DR. R. CANFIELD) MAJOR ACTIVITIES FOR THE MONTHS OF JULY AND AUGUST The main activities of the reporting period consisted of Mees and Yohkoh observations and support, analysis of flares and active regions, and improvement and documentation of observations. The Mees observers continued their regular observations in support of Yohkoh. Magnetograms were obtained with both the Stokes polarimeter and the new IVM, and imaging spectra and coronal limb videos were obtained in H-alpha. Solar activity was rather low. Hudson supported SXT operations in Japan, and Mickey and Leka carried out shakedown observations with the IVM. Noteworthy IVM magnetogram sequences were obtained for AR7216, AR7220 and AR7222 in July, and AR7260 in August. Mickey, Leka, and Metcalf prepared for getting the IVM into daily operation. Mickey and Leka trained the observers at Mees Observatory. Observing programs were defined, twenty hours of training was provided to each observer, and data-quality checks were implemented. As of mid-August, IVM data are being logged in SPAM. We began the analysis of the 1992 July 16 16:55 UT flare. This event is interesting since it is a fairly large (M7) flare, yet it occurred in a region with low magnetic field strength (< 200 G). Wuelser began the analysis of the MCCD data. Metcalf analyzed the Stokes magnetogram. Mickey and Leka analyzed the IVM magnetograms. Metcalf and Kiernan finished up the Yohkoh pointing information for the SPAM database. Kiernan now has SPAM set up for the Yohkoh flare data, and is reading data onto the SPAM Yohkoh flare log. All the 1991 data are now in the SPAM log, as well as the first few months of 1992. Wuelser completed the analysis of the early phase of the November 15 flare in terms of the chromospheric evaporation model, including an analysis of the momentum content of H-alpha and X-ray plasmas. He is now writing up the results as a paper for the Astrophysical Journal. Metcalf analyzed Stokes magnetogram data for the January 5, 1992 flare and did the co-alignment between the Mees magnetogram and the SXT images. He sent these data to Doschek for his study of this event. Metcalf worked on the final co-alignment of the currents and SXT images from AR6952, and has started writing the paper. Metcalf and Jiao worked on the study of the height dependence of the chromospheric magnetic field using Na-D data, and Leka and Canfield finished writing the papers on currents and flare processes. Metcalf and Mickey made a preliminary comparison of IVM and Stokes magnetograms. This revealed problems with the liquid crystal shutters. Mickey and Leka devised a way of compensating for this problem in the data reduction. The IVM and Stokes magnetograms can now be brought into satisfactory agreement, bearing in mind the spatial resolution difference. The IVM calibration matrix is now much superior to that of the Stokes polarimeter, an encouraging development indeed. Weber completed his term as IVM programmer with improvements to the file management and data logging functions. Page 5 PLANS FOR SEPTEMBER AND OCTOBER Support of the Yohkoh and Mees operations will continue by Hudson and the Mees observers. We will begin the transition of the IVM operation from Mickey and Leka to the regular Mees observers by getting IVM vector magnetograms two or more times daily on the important active regions. Wuelser will visit ISAS from September 9 to October 5. He will continue the multispectral analysis of the 1992 July 16 flare. Hudson will report on his July-August work, as well as his September-October work. Kiernan will bring the SPAM Yohkoh database up to the present, and will finish the multi-observatory search capability. Metcalf will wrap up his AR6952 study and to continue to work with Jiao studying the height dependence of the magnetic field using a combination of Na-D and FeI magnetograph data. They plan to complete the study of the extent to which the field is force-free and then work on using the Na data to resolve the 180 degree ambiguity in the magnetic field measurements. Mickey will investigate replacement of the liquid crystal shutters with mechanical ones, as it appears reliability is more important than speed. He will also install stiffer mounts for two fold mirrors to reduce sensitivity to external vibrations, and to make minor improvements to the power distribution and filtering. He will design the required modifications to restore the IVM spatial resolution to its original design level. Leka will assess the quality of IVM data she obtained of the region AR7260 during its rapid growth in the trailer spot region, to judge its applicability for her thesis research. Leka will investigate the region's electric current-carrying properties as it emerged, and also investigate the coronal counterparts to this emerging flux by utilizing data from SXT. The analysis of this dataset will be the focus of her work when she arrives in Japan to work at ISAS for the period 27 October to 22 November. -------------------------------------------------------------------------------- UNIVERSITY OF CALIFORNIA AT BERKELEY (Dr. S. R. Kane) S.R. Kane is presenting a paper at the COSPAR meeting which is taking place in Washington, D.C. from August 1 to September 5, 1992. This paper continues work on the 2-NOV-91 and 15-NOV-91 flares, using the Yohkoh SXT, HXT and WBS along with data from the GOES, Ulysses and PVO spacecraft. This work will be prepared for publication and submitted soon. Another paper, by J. McTiernan, with other SXT team members, on the temperature and density structure of flares, is also being readied for publication. McTiernan is also working on the comparison of thick-target electron beam models with HXT results, and has presented some results at a Solar Neighborhood meeting, at OVRO on July 31, 1992. A student, Terry Slocum, is presently working on summary plots of WBS flare data, with the future intention of doing some statistical studies of Hard X-ray flares, and the active regions responsible for them. A final version of the IDL version of the HXT image synthesis program, adapted from the MOVIE program of T.Sakao, by J. McTiernan and M. Morrison, is nearly complete. This program will create image files which can be included with the reformatted data base, and read by the same software. A release version of the SXT temperature software, written last year by J.McTiernan, properly documented, is next in line, and should be finished in the next couple of weeks. Page 6 -------------------------------------------------------------------------------- STANFORD UNIVERSITY (DR. P. STURROCK) Our main Yohkoh-related activities during this reporting period are as follows. Jim Klimchuk attended the SOHO Workshop on Coronal Loops, Coronal Streamers, and Coronal and Solar Wind Composition. There, he gave an invited talk entitled "Static and Dynamic Loop Models and Their Observational Signatures," and he took the opportunity to describe preliminary Yohkoh results whenever the situation arose, both during the public sessions and in private. He discussed possible CME collaborations with several interested scientists, including Dick Altrock, who would provide forbidden line coronagraph data from Sac Peak. Klimchuk, Kevin Kluge, George Roumeliotis, Taeil Bai, and Lisa Porter attended the Solar Neighborhood Meeting at Owens Valley Radio Observatory, where they gave talks entitled "Coronal Mass Ejections: Preliminary Results from Yohkoh" (Klimchuk), "Loss of Equilibrium as a Possible Explanation for CMEs" (Roumeliotis), "The 154-Day Periodicity" (Bai), and "Dissipative Mechanisms for Coronal Heating by Waves" (Porter). Kluge and Klimchuk have examined all the full-frame SXT data for the periods when HAO's Mark III coronagraph on Mauna Loa was observing and have identified 12 X-ray eruptive events with approximate speeds exceeding 25 km/sec. They have also begun to identify eruptive events (at all times) in Keith Strong's desaturated image video. Roumeliotis has fitted coronal loops observed in full-resolution SXT images with a function corresponding to a uniform circular cross- section and infers loop diameters of approximately 4000 km. He has also continued his work on deconvolving SXT images using the maximum likelihood method. Peter Sturrock has obtained a list of nine H-alpha surges from Francis Tang at Caltech and finds that five of them were observed by SXT. He and Bai plan to compare the H-alpha and X-ray data. During the next reporting period, we plan to continue this work in progress. -------------------------------------------------------------------------------- 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. The SXT bibliography consists 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. In addition to maintaining the bibliography in Tucson, it also resides on sxt3 in Palo Alto for access by Lockheed individuals: located in /usr/people/harvey/sxt.bibliography. This will be updated periodically. (3) Assisted in data analysis and writing of a paper on the lifetime distribution of X-ray bright points. This will be presented at the 1992 COSPAR meeting in Baltimore in August. Paper is entitled `Lifetimes and Distribution of Coronal Bright Points Observed with Yohkoh', by K. L. Harvey, K. T. Strong, N. Nitta, and S. Tsuneta. Paper is to be presented by K. T. Strong. 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 | September 10, 1992 August 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ No. Delivered From Subject Lines 2 Sep 9 11:33 LACTON SXT Progress Report 404 <<< END >>> Wednesday, Sep 9, 1992 1:09 PM PDT