Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for June 1994) 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 30 August 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 PROGRAMMATIC ACTIVITIES IN THE MONTH Operational and analysis activities are continuing in normal fashion. The extended mission activities have been defined more clearly, and the current plan is to extend mission operations through 30 September 1995 under the current contract. In addition a new contract is to be implemented for two additional years through 30 September 1997, and add on a year of Data Analysis through 30 September 1998. The contract is to be structured so that each year becomes an exercisable option at the discretion of the government. << Solar Activity >> The Sun started the month at a low level of activity, however the NOAA AR7742/3 complex produced a series of small flares that culminated in an M2.5 event on 30 June peaking at 21:30 U.T. in the middle of a Yohkoh daylight period. SXT obtained excellent preflare and flare data throughout the event.. This active-region complex was the return of AR7732 which rapidly emerged in an area of quiet Sun in the southern hemisphere and continued to grow steadily on the far side of the Sun. Several new active regions emerged this month, interestingly in an almost perfect straight line stretching across the entire disk (NOAA ARs 7730, 7735, 7736, 7737, 7738, and 7739). Based on our SMM experience, we can expect short, infrequent bursts of such activity throughout the rest of the decline of this cycle and during solar minimum. The fact that Page 2 these regions seemed to emerge over much of the Sun at similar times may point to a large-scale driver for active-region emergence rather than regions of activity emerging separately at active longitudes. SXT, with its high sensitivity and long-term data base, should make it possible to build an unprecedented statistical picture of how magnetic flux emergence works, especially during these quiet periods and during the onset of the next cycle when there are fewer and simpler magnetic structures to confuse the overall picture. In June there continued to be minor large-scale activity, mainly near the AR7742 complex. However there seem to have been none of the major polar crown filament eruptions that have characterized the last few months. X-ray bright points abound and still show the high degree of variability that we have seen since launch. << Campaigns >> We completed the "Chromospheric ejections and coronal loops" campaign on 3 June 1994 organized by B. Schmieder, L. van Driel, and P. Mein. D. Alexander ran the campaign as chief observer. The SXT team ran a second campaign, organized by Sarah Martin, to look at the evolution of prominences and filaments, coordinating H-alpha, magnetogram, and Yohkoh observations. This was notable as being the first opportunity to get the SOON network to support such a campaign (thanks to Alan Kiplinger). << Science >> Much of our science activity is described in the group reports that are attached to the end of this report. Many of us are preparing talks and drafting papers for the upcoming COSPAR meeting in Hamburg, Germany, as well as planning for the SOHO workshop that will take place in Boulder in September. There continues to be a healthy flow of new science topics to the electronic Team Bulletin Board. Much of the new activity is associated with solar minimum and large-scale phenomena. Work continues on comparisons with Ulysses, NIXT, SERTS, and SPARTAN. Although many of those groups are "on hold" while they prepare proposals to the Yohkoh G.I. Programme. We had several visitors at LSAL. Professor J. L. Culhane of Mullard Space Science Laboratory visited for a day this month to discuss analysis of SXT data to interpret the Page 3 structure and physical conditions in a coronal hole with the Yohkoh team. He was particularly interested in the results coming out of the SPARTAN-Yohkoh joint analysis. Dr. Simon Plunkett from the University of Birmingham, U.K., visited the Solar and Astrophysics Laboratory for three weeks to work on a project to study sympathetic flares with Keith Strong. He is using SXT full-disk images of the solar corona to see evidence for energy transport in the large-scale loops that often connect active regions. << Papers and Conferences >> We listed the numerous AGU/SPD talks given by the Yohkoh team and that included Yohkoh data in the last report. A somewhat more comprehensive lists may be found in the individual group reports at the end of this report. - Papers Published (2) - "Electric Currents and Coronal Heating in NOAA Active Region 6952", T. R. Metcalf, R. C. Canfield, H. S. Hudson, D. L. Mickey, J.-P. Wuelser, P. C. H. Martens, and S. Tsuneta, Astrophys. J. 428, 860. "High Energy Gamma-ray Emission from Solar Flares: Constraining the Accelerated Proton Spectrum" D. Alexander, P. Dunphy, A. L. MacKinnon, Solar Physics, 151, 147, (1994) - Papers accepted (4) - "The Possible Role of MHD Waves in the Heating of the Solar Corona," Porter, L. J., Klimchuk, J. A., and Sturrock, P. A., Ap.J. "The Possible Role of MHD Waves in the Heating of Solar Coronal Loops," Porter, L. J., Klimchuk, J. A., and Sturrock, P. A., Ap.J. "The 1991 October 24 Flare: A Challenge for Standard Models" J.-F. de la Beaujardiere, R.C. Canfield, H.S. Hudson, J.-P. Wuelser, L.W. Acton, T. Kosugi, S. Masuda, Astrophys. J. "Particle acceleration and the decay of soft X-ray non-thermal line broadening in solar flares" D. Alexander and S. A. Matthews, accepted for publication in Solar Physics - Papers submitted (3) - Page 4 "A New Method for Reconstructing the Coronal Magnetic Field," Roumeliotis, G., Ap.J. "Is the Solar Chromospheric Magnetic Field Force-Free?", Thomas R. Metcalf, Litao Jiao, Han Uitenbroek, Alexander N. McClymont, and Richard C. Canfield, Astrophys. J. "Resolving the 180 Degree Ambiguity in Vector Magnetic Field Measurements: The 'Minimum' Energy Solution", Thomas R. Metcalf, Solar Phys. - Presentations (1) - "The Violent Corona", Keith Strong, San Jose Tech Museum, - Abstracts (3) - "The Large Scale Coronal Eruptive Event of April 14 1994" D. Alexander, G. Slater, H. Hudson, A. McAllister and K. Harvey, SoHO Workshop in Estes Park, Colorado in September "Differential Rotation in the Solar Corona" M. Weber, L. Acton, D. Alexander, SoHO Workshop in Estes Park, Colorado in September "Non-thermal Soft X-ray Line Broadening in Gamma-ray Flares" David Alexander and Sarah A. Matthews, COSPAR, Hamburg, July 11-21 << Public Use of SXT Images >> 10,000 posters were sent by Gary Linford to NASA Headquarters for the distribution to various HQ offices, NASA Centers, and NASA Educational Resource Centers. We are now down to less than 5K posters. Further requests come flooding in for these new posters and for the PR videos we have prepared. Gary Linford and Keith Strong prepared another in the series of monthly articles for Sky & Telescope. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function well with a normal level of Single Event Upsets (SEUs). No significant degradation in the instrument has occurred since the loss of the front thermal shield in 1992. The SEU problems suffered by SXT in June 1994 are as follows: SXT BITMAP ERROR 9 June, Pass 1 10 June, Pass 1 11 June, Pass 1 SXT SYNC1 ERROR 17 June, Pass 2 SXT TABLE ERROR 25 June, Pass 2 Page 5 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Jan-92 5544 3177 10084 5972 16056 6849 29.90 Feb-92 5305 2803 16932 11382 28314 12019 29.80 Mar-92 6248 2361 20367 2653 23020 9458 29.12 Apr-92 6734 3500 20094 5423 25517 12390 32.69 May-92 7032 3158 25464 4589 30053 13745 31.38 Jun-92 7230 2819 24375 13361 37736 11419 23.23 Jul-92 6535 3085 24622 11481 36103 13065 26.57 Aug-92 6572 2978 24207 11154 35361 13550 27.70 Sep-92 6087 2916 26832 20042 46874 15729 25.12 Oct-92 6753 2552 51037 14709 65746 23529 26.36 Nov-92 6648 2949 24345 14832 39177 12859 24.71 Dec-92 6766 3008 24188 6600 30788 12454 28.80 Jan-93 6888 3351 24067 4861 28928 13069 31.12 Feb-93 6833 3004 24479 18149 42628 12302 22.40 Mar-93 7177 3460 25874 19537 45411 14657 24.40 Apr-93 7754 3644 34128 8352 42480 17967 29.72 May-93 8571 3950 41832 7518 49350 21971 30.81 Jun-93 7340 2589 64545 12539 77084 26299 25.44 Jul-93 8259 3650 47561 5352 52913 24213 31.39 Aug-93 7628 3638 30705 3563 34268 17436 33.72 Sep-93 6875 2899 22697 5600 28297 11252 28.45 Oct-93 7474 3657 33782 7548 41330 20104 32.72 Nov-93 8504 3864 42953 5849 48802 23896 32.87 Dec-93 5898 3047 21128 13297 34425 13001 27.41 Jan-94 6934 2804 28567 10960 39527 13746 25.80 Feb-94 6948 2892 22815 5819 28634 11463 28.59 Mar-94 7736 2627 69273 3733 73006 31464 30.12 Apr-94 6142 2741 22707 3390 26097 12338 32.10 May-94 6369 2395 22918 2251 25169 9737 27.89 Total 215594 98112 917295 308027 1225322 478707 28.09 Number of Full Frame Images Received: 215594 Number of Observing Region Images Received: 1225322 Total: 1440916 Approximate Number of Shutter Moves/CCD Readouts: 2520973 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 (%) Jan-92 31.13 23.6 985 450 0.5 / 2 14.9 38.4 Feb-92 31.32 30.8 1176 544 14.3 31.7 Mar-92 31.47 36.5 1355 626 14.8 25.1 Apr-92 31.44 35.2 1323 610 23.8 / 4 14.6 22.8 May-92 31.65 43.1 1417 653 14.4 20.1 Jun-92 32.12 60.9 2215 880 -2.5 / 3 15.1 17.4 Jul-92 32.19 63.2 1829 822 15.5 14.1 Aug-92 32.21 64.1 1922 886 14.9 13.1 Sep-92 32.38 70.5 2062 954 -1.2 / 3 15.9 12.2 Oct-92 32.64 80.3 2317 1055 16.8 11.5 Nov-92 36.24 215.1 6112 1391 18.0 11.0 Dec-92 42.58 452.8 17390 2024 17.9 N/A Jan-93 42.59 453.1 13006 2034 23.8 / 2 19.2 N/A Feb-93 42.28 441.5 13895 2090 17.7 N/A Mar-93 43.14 473.8 14047 2151 17.7 N/A Apr-93 43.13 473.4 14304 2146 23.8 / 2 16.9 N/A May-93 43.45 485.3 16405 2357 17.3 N/A Jun-93 44.03 507.2 20037 2531 16.3 N/A Jul-93 44.52 525.6 23977 2700 22.5 / 2 17.7 N/A Aug-93 44.24 515.0 21879 2643 25.2 / 3 17.2 N/A Sep-93 45.07 546.2 27469 2745 17.5 N/A Oct-93 45.40 558.6 31684 2982 17.7 N/A Nov-93 45.33 555.8 32047 3210 23.8 / 3 19.7 N/A Dec-93 45.92 578.1 38515 3101 19.2 N/A Jan-94 46.18 587.9 42560 3464 22.5 / 2 20.3 N/A Feb-94 46.03 582.1 40449 3246 19.3 N/A Mar-94 45.92 578.0 39715 3420 18.2 N/A Apr-94 45.97 579.9 41302 3721 25.2 / 3 17.8 N/A May-94 46.25 590.3 45476 3557 18.4 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 Page 7 << Personnel Travel >> SXT travel for the month of June 1994: ALEXANDER 1-JUN-94 * 4-JUN-94 4 (total of 4 days) BRUNER 1-JUN-94 * 7-JUN-94 7 (total of 7 days) FREELAND 20-JUN-94 30-JUN-94 * 11 (total of 11 days) HANDY 1-JUN-94 30-JUN-94 * 30 (total of 30 days) HUDSON 1-JUN-94 * 20-JUN-94 20 26-JUN-94 30-JUN-94 * 5 (total of 25 days) LEMEN 7-JUN-94 30-JUN-94 * 24 (total of 24 days) NITTA 20-JUN-94 30-JUN-94 * 11 (total of 11 days) SLATER 1-JUN-94 * 8-JUN-94 8 (total of 8 days) LABONTE 1-JUN-94 * 30-JUN-94 * 30 (total of 30 days) METCALF 7-JUN-94 30-JUN-94 * 24 (total of 24 days) ---------------------------------------------------------------- Grand Total of 174 days for 10 people Planned SXT travel for the month of July 1994: FREELAND 1-JUL-94 * 20-JUL-94 20 (total of 20 days) HANDY 1-JUL-94 * 30-JUL-94 30 (total of 30 days) HUDSON 1-JUL-94 * 10-JUL-94 10 28-JUL-94 31-JUL-94 * 4 (total of 14 days) LEMEN 1-JUL-94 * 29-JUL-94 29 (total of 29 days) LINFORD 26-JUL-94 31-JUL-94 * 6 (total of 6 days) NITTA 1-JUL-94 * 10-JUL-94 10 27-JUL-94 31-JUL-94 * 5 (total of 15 days) LABONTE 1-JUL-94 * 25-JUL-94 25 (total of 25 days) METCALF 1-JUL-94 * 1-JUL-94 1 (total of 1 days) MCTIERNAN 17-JUL-94 30-JUL-94 14 (total of 14 days) ---------------------------------------------------------------- Grand Total of 154 days for 9 people NOTE: The "*" signifies travel that actually ends after 31-JUL-94 Respectfully submitted, Keith T. Strong 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 July 1994 June 1994 |------------------------------- | 6. PERFORMING ORG | CODE: O/91-30 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- K. T. Strong | 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 June 1994 |------------------------------- |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 | 16 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-0001 Page 9 MONTANA STATE UNIVERSITY (LOREN ACTON) for May - June 1994 If you get a chance to see the just-released IMAX movie "Destiny in Space" you should definitely do so. The movie includes a short segment of SXT images prepared by JPL and they are spectatcular! This has been an active and productive bimester for the MSU Solar Group. In May, Brian Handy successfully completed the oral portion of his PhD qualifying exam with a talk on spectroscopy of high temperature plasmas. He prepared and gave a poster paper at the Baltimore SPD/AGU meeting on the loop system linking AR7260 and AR7264, observed by YOHKOH in August 1992. He is now at ISAS in training as an SXT Chief Observer. We are pleased to report that Mark Weber has joined the group and intends to do a PhD thesis on solar physics. Weber is doing a summer project on differential rotation of the corona by doing time-series analysis of the signal in longitude/latitude bins extracted from the SXT composite images. Mark is the winner of a research fellowship from the Montana Space Grant Consortium which will support his PhD research. David Alexander spent May at ISAS as SXT Chief Observer. His efforts to observe the May partial eclipse with SXT was frustrated by Murphy's Law but he is keen to give it another go in November. He is working on interpretation of the great 14-Apr-94 south polar CME along with Hudson, McAllister and others. In June, Alexander attended the IACG workshop in Japan and the Solar Probe workshop at HAO. Loren Acton visited LPARL in May, on the way home from 3 months at ISAS, to help with a proposal with Jim Lemen and others aimed towards improving public access to SXT imagery over the Internet. He prepared and presented a contributed and an invited paper at the AGU/SPD meeting at Baltimore and was extremely pleased to see the many uses of SXT data appearing in papers at this meeting. Len Culhane visited MSU for a few days in early June and worked with Acton on an attempt to characterize the intensity lapse rate over the south polar coronal hole (with Hudson and Phillips). This work prompted revisiting the x-ray scattering problem -- an SXT Calibration Note was prepared on this subject. In late June, Acton visited HAO to discuss CME studies with Art Hundhausen and x-ray irradiance publication with O. R. White. This is intended as the first step in an on-going collaboration with HAO workers on these subjects. Finally, at the end of June, Acton visited LPARL to help write the proposal to extend operations of SXT for the 1-Sep-94 to 30-Sep-95 time period. Page 10 SOLAR PHYSICS RESEARCH CORPORATION (KAREN L. HARVEY) Activity the last two months are as follows: 1. continuation of the multi-observatory collaborative observing program to study X-ray bright points. The latest observing campaign took place 16 June to 22 June 1994 and involved the Yohkoh SXT, NSO/KP, BBSO, and MSO. The objective of this run was to study variations and the association of He I 10830 dark points and X-ray bright points. This run was marginally successful at NSO/KP; we were only able to obtain data on the first and last day of the run. Because July and August are our normal monsoon season with cloud build-ups, rain, and lightening storms, I will not request in August additional collaborative observations with Yohkoh SXT on XBP. 2. attended the AGU/SPD meeting in late May and presented a poster paper on X-Ray Bright Points: The Signature of Magnetic Field Reconnection, Authors: Karen L Harvey, Frances Tang, Hal Zirin, Sara Martin, Hugh Hudson, Don Mickey, Marilyn Bruner, James Lemen, Keith Strong, Nariaki Nitta, Saku Tsuneta 3. continued updating of bibliography of Yohkoh papers; the bibliography is being restructured for easier access as per conversations with N. Nitta and K. Strong. A list of papers in refereed journals and meeting proceedings separated by year was compiled, and is now available on the Lockheed and ISAS computers. 4. contacted by the producers of `Disney Presents Bill Nye the Science Guy' for an interview on solar astronomy. I met the producer, cameraman, and sound man on 23 June 1994 for a tour of the National Solar Observatory telescopes and facilities at Kitt Peak and for an interview of how exciting it is to be a solar astronomer, what I do, and why the Sun is important to everyone. They will likely show some Yohkoh SXT sequences in the eventual segment that will deal with the Sun. Page 11 STANFORD UNIVERSITY (DR. P. STURROCK) May/June 1994 During this period, our primary Yohkoh activities centered around preparation for and attendance at the joint Solar Physics Division American Geophysical Union meeting held in Baltimore on May 23-27. The following talks were given: "Soft X-Ray Loops and Coronal Heating: Observations" (Porter and Klimchuk), "Soft X-Ray Loops and Coronal Heating: Interpretation" (Klimchuk and Porter), "Inferring the Coronal Magnetic Field from Magnetograph Data" (Roumeliotis), and "Force-Free Magnetic Fields in Curved Flux Tubes" (Sturrock and Glukhov). Klimchuk was also co-author on "The Source Regions of CMEs and the Large-Scale Magnetic Field Using Yohkoh SXT Data" (Webb, Kahler, and Klimchuk) and "Coronal Loop Thickness Variations and Electric Currents" (Jiao, Canfield, and Klimchuk). We are pleased to report that Lisa Porter successfully defended her Ph.D. dissertation entitled "Wave Heating of the Solar Corona." She gave a talk by the same title at the Naval Research Laboratory. The first two parts of the dissertation are concerned with the theory of MHD wave damping by collisional processes (ion viscosity and electron thermal conduction), and the third part is concerned with Yohkoh observations of coronal loops and the constraint that the observed relationship between loop pressure and loop length places on theories of wave (and other) heating. Porter has left Stanford for a post-doc position at the Massachusetts Institute of Technology, where she will teach one course per academic quarter and spend roughly half her time on research. Much of the research will likely be in the area of fusion plasma physics, but she will also continue to collaborate with Klimchuk on Yohkoh problems that they have started. Klimchuk will leave Stanford on July 1 for a staff position in the Solar-Terrestrial Relationships Branch of the Naval Research Laboratory. He will continue to work on Yohkoh problems at a one-quarter time level of effort through a subcontract from Stanford. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * I have greatly enjoyed my time at Stanford and my collaboration with the people at Lockheed. I have been proud to be part of such a first-rate program, and I look forward to continued associations with all the good friends I have made. Jim Klimchuk * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Page 12 UNIVERSITY OF CALIFORNIA AT BERKELEY (DR. S. KANE) J. McTiernan has been working combination BCS-HXT analysis of flares, for a large sample of events, in order to calculate the low energy cutoff of nonthermal emission. Results will be presented at the May '94 SPD meeting in Baltimore. This work will be continued when McTiernan visits ISAS later in July. As a result of some work on the distribution of SXT temperatures presented by J. Klimchuk at the Baltimore meeting, we have gone back and redone a Monte Carlo analysis of the uncertainties of SXT temperature and emission measure determination, using both thick-thick filter ratios and thin-thin filter ratios. (Previous work had only been concerned with the thick-thick and thick-thin cases.) Klimchuk had found, that for the thin-thin filter temperature determination, the distribution of errors is not normal, (i.e., not a Gaussian distribution), and the uncertainty in emission measure can be much larger than that given by the standard error analysis. Our results confirm this for the thin-thin case. For the thick-thick case, the resulting error distribution is normal, and the standard error analysis contained in the routine SXT_TEEM is correct, except when the SXT DN is very small (i.e., low temperatures and short exposures). We speculate that the thin-thin ratio case gives large errors because of the flatness of the filter ratio vs. temperature curve, see Figure 5, section 3.1, of the Yohkoh Instrument guide. A program to calculate uncertainties using the Monte Carlo method will be put on-line shortly, and an SXT calibration note will be issued. S. Kane is presenting results from multispacecraft observations of hard X-rays using Yohkoh, Ulysses and BATSE results, at the COSPAR meeting in Hamburg this month. Page 13 UNIVERSITY OF HAWAII ACTIVITY REPORT (DR. R. CANFIELD) Major Activities for the Months of May and June Our most important activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition at Mees (including three campaigns), development of full-disk observing capabilities, analysis of Yohkoh/Mees data, organization of meetings, participation in meetings, and preparation of manuscripts. Operational support for SXT was provided by Hudson, Metcalf, and LaBonte at ISAS, as SXT Chief Observer (Hudson) and SSOC Toban (all), Judd, Nitta, and Douglass at Mees (observatory operations), and Canfield, Jiao, Leka, Metcalf, and Wuelser in Manoa (Mees Yohkoh Duty Scientist). During May 19 - June 02 the Mees observers carried out observations in support of the Chromospheric Ejections and Coronal Loops campaign (G. Cauzzi, Mees coordinator). During 9 - 15 June, they supported the Hida AFS campaign (G. Cauzzi, Mees coordinator). Finally, during 19 - 22 June, they supported the X-ray bright point campaign (D. Mickey, Mees coordinator). Canfield worked with K. Shibata on the organization of the CDAW on Eruptive Phenomena in the Solar Corona. The dates of the workshop have now been established: November 8 - 11, 1994. He also worked with J de La Beaujardiere and finished the manuscript on the October 24 flare. Finally, he worked with K. Reardon on their study (with K. Shibata, T. Yokoyama, and M. Shimojo) on surges and jets in AR7260. The morphology of the reconnection process involved in these events is clearly related to the "Eiffel tower" morphology discovered by Kurokawa and Kawai in emerging flux surges. Interesting evidence was discovered byer plans to continue his collaboration with Bastian on the August 20, 1992 flare, and to write up his work on chromospheric heating and energetics in large flares. Reardon for both downward and upward jets. During the month of May Wuelser finished his study of the quantitative relationship between chromospheric heating, chromospheric evaporation, and chromospheric and coronal energetics in three large flares. He found that heating by non-thermal electrons is more compatible with the flare energetics, although there are signatures of conductive heating. He presented his results at the Spring meeting of the American Geophysical Union. In June Wuelser focused his work on the well-observed flare of August 20, 1992, in collaboration with Bastian. The exceptional set of coordinated observations (from Yohkoh, Mees, and the VLA) present a unique opportunity to better understand the relationship between energy release, energy transport, and magnetic field in flares. Jiao presented a paper at the AGU/SPD meeting in Baltimore, in collaboration with Canfield and Klimchuk. He also finished his thesis proposal draft on the theoretical modeling of coronal fields based on Mees vector magnetograms and comparison of the results with SXT data. Metcalf worked with J. Lim on the comparison of microwave observations to linear extrapolation of photospheric magnetograms in to the corona, and with N. Nitta on extrapolations of the photospheric field in AR7260. He spent the month of June at ISAS, where he wrote a pair of programs to apply fractal pixon image reconstruction to HXT and SXT data. He continued to work on IVM H-alpha data, for evidence of precipitation of low-energy protons during flares, and began a comparison of the data to Nobeyama radioheliograph data. Leka worked on the quantitative analysis of the currents and magnetic flux in AR7260 and presented preliminary results at the AGU/SPD meeting. She also addressed the comments from the referee of the "Roadmap" paper and resubmitted it to Solar Physics. Hudson attended the AGU/SPD meeting in Baltimore and presented SXT observations of the early phases of the 21-Feb-92 flare, the prototype of SXT cusp events. The early phase included a previously unrecognized blob-like ejection, strongly suggestive of filament eruption as expected to occur in LDE-type flares. At the SOLTIP meeting in Nakaminato, Japan, he presented a general Page 14 review of the SXT observations of the outer corona, including the interesting result that the coronal holes seen in SXT data on the disk are not limb-brightened, as virtually every plausible model would predict. This adds to the mystery of the SXT coronal hole observations. Hudson worked with Lidia van Driel on white-light flares observed by the SXT aspect sensor. Better software enabled them to extend the limit of detection down to the low M level of flare importance; still better software (B. LaBonte) promises to reduce the threshold all the way to the photon statistics and/or p-mode limits. Plans for July and August Wuelser plans to continue his collaboration with Bastian on the August 20, 1992 flare, and to write up his work on chromospheric heating and energetics in large flares. The new mosaic capability of the Mees CCD imaging spectrograph (MCCD) has now been used during two X-ray Bright Point campaigns. Starting in July, Wuelser and collaborators will use the new capability for regularly scheduled observations of quiescent filaments. One of the goals is to study their eruption and to look for simultaneous signatures in the X-ray corona observed by SXT. Jiao plans to reduce Mees magnetograms for about 30 active regions, do the programming associated with sxt loop 3-d reconstruction problem based on previous work (Berton et al 1985, Slater et al 1994), and study the way to improve the existing 3-D magnetic field calculation code proposed for his thesis. Metcalf plans to continue the analysis of the IVM H-alpha polarization data (low energy protons project). He will also continue to work with Roumeliotis on the extrapolation of photospheric magnetic fields into the corona. Leka will complete and submit the centerpiece for her thesis, a paper which defends (with both morphological and quantitative arguments) the hypothesis that emerging flux carries electric current. She will also start writing the chapter of her thesis dealing with the Imaging Vector Magnetograph. Canfield will work with K. Reardon on H-alpha surges and X-ray jets; while in Japan for the Solar-B International meeting, he will work with collaborators there. He will also work on the cost proposal for the extended Yohkoh mission and on the CDAW. Hudson's main focus will remain on the Ulysses/Yohkoh Page 15 comparisons. He intends to submit a rebuttal to the Gosling paper on "The Solar Flare Myth", including analysis of the remarkable event of 14 April 1994. This event will also be reported by Alexander et al. at the Soho workshop in Estes Park. Other projects include studies of meter-wave events in collaboration with the Maryland group, a COSPAR presentation by F. Farnik on remarkable flares of Oct. 3, 1993, and further work on limb brightening in coronal holes. This latter subject is quite important for our understanding of coronal-hole physics and should be written up for publication during this interval. Hudson will attend the Solar-B meeting in Japan in early July, and will make a presentation on the outer corona as seen by SXT. PRESENTATIONS DURING MAY AND JUNE "Patterns of Helicity in Solar Active Regions," A. A. Pevtsov, R. C. Canfield, and T. R. Metcalf AGU 1994 Spring Meeting, 1994. "Coronal Loop Thickness Variations and Electric Currents," L. Jiao, R. C. Canfield, and J. A. Klimchuk AGU 1994 Spring Meeting, 1994. "Diagnostics of Current-Carrying Emerging Flux," K. D. Leka, R. C. Canfield, A. N. McClymont, T. R. Metcalf, and D. L. Mickey AGU 1994 Spring Meeting, 1994. "A Search for Low Energy Protons in Several Solar Flares from October, 1992," T. R. Metcalf, D. L. Mickey, R. C. Canfield, J. P. Wuelser, T. Kosugi, and S. Tsuneta AGU 1994 Spring Meeting, 1994. "Connectivity and Currents in AR 7562," D. L. Mickey, K. D. Leka, and T. R. Metcalf AGU 1994 Spring Meeting, 1994. "X-ray Jets and H-alpha Surges in AR 7260," R. C. Canfield, K. D. Leka, K. P. Reardon, K. Shibata, M. Shimojo, and T. Yokoyama AGU 1994 Spring Meeting, 1994. "Chromospheric Heating and Energetics in Three Large Flares," J.-P. Wuelser, R. C. Canfield, L. W. Acton, T. Kosugi, and J. L. Culhane AGU 1994 Spring Meeting, 1994. "Coronal Rays as Observed by Spartan 201 Externally Occulted Coronagraph, HAO's K-Coronameter, and Soft X-ray Telescope from Yohkoh on April 11, 12, 1993", R. R. Fisher, M. Guhathakurta, D. G. Sime, T. E. Holzer, K. Strong, N. Nitta, L., Acton, H. Hudson, Y. Ogawara, S. Page 16 Tsuneta, T. Watanabe, AGU 1994 Spring Meeting, 1994. "Yohkoh and SPARTAN Observations of Large-Scale Coronal Activity", K. Strong, H. Hudson, R. Fisher, M. Guhathakurta, S. Habbal, and N. Nitta, AGU 1994 Spring Meeting, 1994. "Coordinated cm and X-ray Observations of an Active Region Streamer", S. R. Habbal, A. Mossman, M. Karovska, R. Gonzalez, and H. Hudson, AGU 1994 Spring Meeting, 1994. "The Timing and Energetics of an X-ray Mass Ejection in a Slow LDE Flare", H.S. Hudson, J.R. Lemen, and S. Tsuneta, AGU 1994 Spring Meeting, 1994. "X-ray Bright Points: The Signature of Magnetic Field Reconnection," K. L. Harvey, F. Tang, H. Zirin, S. Martin, H. Hudson, D. Mickey, M. Bruner, J. Lemen, K. Strong, N. Nitta, and S. Tsuneta, AGU 1994 Spring Meeting, 1994. "Creation and Heating of Inter-region Coronal Loops", B. N. Handy, L.W. Acton, D. Alexander, T. R. Metcalf, H.S. Hudson, and T. Shimizu, AGU 1994 Spring Meeting, 1994. "Stereoscopic Determination of Coronal Loop Geometries using SXT Data", G. L. Slater, H.S. Hudson, and S. L. Freeland, AGU 1994 Spring Meeting, 1994. "Image Reconstruction and Enhancement of Yohkoh X-ray Observations of the Sun", M. Karovska and H. Hudson, AGU 1994 Spring Meeting, 1994. "Multiwavelength Coverage of the 7 January 1992 Flare", A. Silva, I. de Pater, R. P. Lin, J. M. McTiernan, D. E. Gary, H.S. Hudson, M. J. Hagyard, J. G. Doyle, S. M. White, M. R. Kundu, AGU 1994 Spring Meeting, 1994. "Estimating Solar Soft X-ray Forcing of the Middle Atmosphere from Yohkoh SXT Data", J. Lean, J. Mariska, K. Strong, H. Hara, and H. Hudson, AGU 1994 Spring Meeting, 1994. "The Structure of the Extended Corona: Comparison with Solar Wind Models", J.R. Lemen, H.S. Hudson, and L.W. Acton, AGU 1994 Spring Meeting, 1994. "Solar Flare Temperature vs. Emission Measure Plots from Fe XXV and Wide-Band Soft X-ray Data", A. C. Sterling, G. A. Doschek, H.S. Hudson, and T. Watanabe, AGU 1994 Spring Meeting, 1994. "Yohkoh, OVRO, and BBSO Observations of a Solar Flare", D. E. Gary, S. Masuda, T. Kosugi, and H.S. Hudson, AGU 1994 Page 17 Spring Meeting, 1994.