Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for July 1997) 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, 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 Palo Alto Research 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 The 1997 Senior Review of Sun-Earth Connection Operating Missions report was published and was very favorable to the Yohkoh mission. Preparations are being made by MSFC to issue an RFP that allows continuing operations of SXT for 1998 and for enhanced scientific support. << Solar Activity >> During the first half of July, solar activity was again quite low. A GOES C-Class level flare occurred and a new-cycle region crossing the W limb on about 12 July. There were four numbered NOAA regions, maximum sunspot area 30 millionths and two listed GOES events. However, small new-cycle regions continue to appear. The quite remarkable streamer bottom observed on June 21 (E limb) and July 5 (W limb) returned to the E limb. This has an exceptionally well-defined cavity, bulging outwards in a manner reminiscent of the celebrated 21 Feb 1992 flare event. Plus, an X-ray bright region surrounding the filament. This structure seems to be bringing us some new facts about filaments. Later in the month, solar activity was medium, with quite a few B-class flares from a string of weak active regions in the N. These faded by late July. On August 2, a B-class flare happened at exactly 00:00 UT. A nice CME happened on July 30, leaving a beautiful arcade for SXT to see. Page 2 << Campaigns >> SXT supported a campaign with the VLA and SoHO to observe AR 8059, a new-cycle region crossing the W limb on about 12 July. There were also coordinated observations with CDS during week 28, looking at AR loops. The data set looks good and will perhaps be one of the featured items at the 2nd SOHO/Yohkoh CDAW, to take place at Medoc (Paris) in October. In late July/early August, SXT ran a 10'x10' X-ray Bright Point (XBP) program in coordination with various partners, specifically MDI, CDS, and KPNO (Lee McDonald is a coordinator at ISAS). Some of the inspiration for this came from the nice paper on "network flares" by Krucker et al., and by glowing accounts of a movie that Alan Title showed at the Cool Stars meeting, in which MDI and CDS played starring roles. << Science >> Acton presented a paper at the SPD meeting on the accuracy of conversion of SXT full-disk signals to mean temperature and spectral irradiance. That paper (with Weston and Bruner) has finally been submitted to Solar Physics. Canfield presented several papers at the SPD meeting related to magnetic helicity. Alexander, Lemen, and Metcalf presented SPD posters describing progress in image analysis for SXT and HXT. McKenzie continued research on periodicities in SXT data, and performed some analysis suggested by Julia Saba to test for lower-confidence periods in regions of the loops other than those regions which showed periods at 99.5% confidence. The idea is to see if the same period turns up in several portions of the same loop, even if the confidence is lower than 99.5%. I had performed this test with confidences as low as 95%, but Dr. Saba suggested that periods seen at much lower confidence levels might still be significant. He examined periods seen with at least 75% confidence and is now trying to interpret the results. McKenzie also examined some dense, very transient, brightenings seen near a flaring region on 1993 Aug 21 -- most visible as fine structure in the leg of a sharply cusped loop at UT 15:53:07. Metcalf began re-reducing IVM data from 1996 June 6 for a collaboration with Dana Longcope and George Fisher on their SOHO JOP. The re-reduction is necessary due to the great improvement in the IVM reduction software by Don Mickey and Barry LaBonte. The improvement in the magnetic field measurement for the 960606 data is impressive. The reduction is very compute intensive so it is progressing slowly. The paper on the Masuda event by Alexander and Metcalf was accepted. The preprint is at ftp://wind.space.lockheed.com/pub/metcalf/920113/preprint.ps. << 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 Lockheed SXT WWW homepage (http://www.space.lockheed.com/SXT/). We receive requests for the Page 3 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 39472 accesses and 964 Mbytes transferred. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. There has been no further increase in stray light since 25 August 1996. The quiet patrol image has been changed to Al/Mg (DPE=17) to try to improve the performance of the active region selection algorithm for times when the Sun is very quiet. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT bit map error 10-Jul-97 Pass 2: 970710-1136 recovered in the same pass SXT shutter error 19-Jul-97 Pass 2: 970719-0928 recovered in the 3rd pass SXT bit map error 26-Jul-97 Pass 1: 970726-0515 recovered in the same pass SXT filter soft error 31-Jul-97 Pass 1: 970731-0411 recovered in the 3rd pass SXT bit map error 05-Aug-97 Pass 4: 970805-0618 recovered in the same pass Page 4 << Data Flow >> Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Apr-95 291528 125048 1240419 344823 1585242 613712 27.56 May-95 7084 2884 29617 2647 32264 15331 32.21 Jun-95 7210 3087 25251 307 25558 12045 32.03 Jul-95 6418 4145 21180 1639 22819 15109 39.84 Aug-95 7683 2597 26115 2181 28296 10537 27.13 Sep-95 6546 2853 22006 1753 23759 10433 30.51 Oct-95 6937 3502 22177 3853 26030 13044 33.38 Nov-95 5745 2944 21252 517 21769 12119 35.76 Dec-95 6163 2615 24059 901 24960 11652 31.83 Jan-96 6474 2530 27015 1708 28723 14151 33.01 Feb-96 6200 2581 21380 890 22270 10773 32.60 Mar-96 6908 2869 25437 1460 26897 12274 31.33 Apr-96 7172 2124 45445 671 46116 18848 29.01 May-96 6925 2426 30272 1089 31361 12367 28.28 Jun-96 7515 2723 31952 1536 33488 14521 30.25 Jul-96 5954 1995 29886 4769 34655 12427 26.39 Aug-96 7214 3010 21187 1607 22794 9887 30.25 Sep-96 6904 2618 29906 303 30209 12663 29.54 Oct-96 7405 2853 16463 1842 18305 8034 30.50 Nov-96 7001 2296 24292 5395 29687 9340 23.93 Dec-96 7144 2643 25331 2087 27418 10412 27.52 Jan-97 7186 2747 21126 1257 22383 9915 30.70 Feb-97 6016 2034 22097 1072 23169 8961 27.89 Mar-97 7152 1300 26991 1209 28200 6394 18.48 Apr-97 6018 1055 23639 3890 27529 5349 16.27 May-97 7703 1455 29574 3783 33357 7121 17.59 Jun-97 7398 4434 24604 1396 26000 21890 45.71 Jul-97 0 0 0 0 0 0 0.00 Aug-97 0 0 0 0 0 0 0.00 Total 469603 193368 1908673 394585 2303258 919309 28.53 Number of Full Frame Images Received: 469603 Number of Observing Region Images Received: 2303258 Total: 2772861 Approximate Number of Shutter Moves/CCD Readouts: 4875607 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-95 48.73 683.4 94000 5820 18.8 N/A Jun-95 49.08 696.3 100780 6281 19.6 N/A Jul-95 49.34 706.2 106408 6628 18.1 N/A Aug-95 49.72 720.4 114414 7101 19.5 N/A Sep-95 49.79 723.1 115165 7222 19.6 N/A Oct-95 50.29 741.9 126452 7911 20.2 N/A Nov-95 50.11 735.1 122163 7814 25.2 / 2 20.3 N/A Dec-95 50.19 737.9 123705 7927 22.6 N/A Jan-96 50.81 761.3 136197 8888 21.5 N/A Feb-96 50.67 755.8 133263 8705 22.5 / 2 21.5 N/A Mar-96 50.85 762.9 136982 8973 20.3 N/A Apr-96 51.14 773.6 142250 9500 19.9 N/A May-96 51.16 774.4 140697 10018 19.1 N/A Jun-96 51.56 789.2 147705 10634 20.7 N/A Jul-96 57.45 1010.2 146293 12228 19.8 N/A Aug-96 52.58 827.5 165676 12393 19.6 N/A Sep-96 52.47 823.3 162784 12350 20.0 N/A Oct-96 52.21 813.8 157689 12047 22.5 / 2 21.3 N/A Nov-96 52.45 822.9 161683 12534 21.9 N/A Dec-96 53.08 846.2 171224 13860 22.9 N/A Jan-97 52.35 818.9 164785 11354 23.8 / 7 23.3 N/A Feb-97 51.95 803.9 159426 10346 21.1 N/A Mar-97 55.99 955.6 158428 12190 21.2 N/A Apr-97 53.14 848.4 176207 13265 20.8 N/A May-97 52.96 841.7 172052 13094 20.7 N/A Jun-97 53.69 869.1 182481 14855 19.8 N/A Jul-97 N/A N/A N/A N/A 0.0 N/A Aug-97 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-JUL-97 and 31-JUL-97 HUDSON 3-JUL-97 31-JUL-97 * 29 (total of 29 days) NITTA 30-JUL-97 31-JUL-97 * 2 (total of 2 days) SAVY 1-JUL-97 * 31-JUL-97 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 62 days for 3 people NOTE: The "*" signifies travel that actually ends after 31-JUL-97 SXT Foreign Travel between 1-AUG-97 and 31-AUG-97 HUDSON 1-AUG-97 * 25-AUG-97 25 28-AUG-97 31-AUG-97 * 4 (total of 29 days) NITTA 1-AUG-97 * 31-AUG-97 * 31 (total of 31 days) SAVY 1-AUG-97 * 31-AUG-97 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 91 days for 3 people Respectfully submitted, Thomas R. Metcalf Frank M. Friedlaender Page 7 ================================================================= Montana State Univ Activity Report for June 1997-July 1997 ================================================================= (L. W. Acton) INTRODUCTION Montana has once again provided us with a gorgeous summer as a backdrop for our scientific efforts. Between meetings, research, and travel, the MSU Solar Group have stayed as busy as ever they are during the academic year. We are also looking to increase our numbers by advertising an open position for a Research Scientist who can assist with computer systems management. The MSU Solar Group has been working on establishing a system to write Yohkoh data to CDs. Alex Pevtsov has been writing the IDL codes for this, and undergraduate Jen Greenfield will assist with the massive job of transferring several years' worth of weekly data. SCIENTIFIC ANALYSIS and PUBLICATIONS: Loren Acton has finished up a recent project on the accuracy of conversion of SXT full-disk signals to mean temperature and spectral irradiance. He has also been included as a co-author on some work of Eric Priest which has grown out of Acton's previous investigations of temperature versus height in closed coronal structures away from active regions. One paper on this has been accepted by Nature and a complete paper is in preparation for submission to ApJ. Richard Canfield worked with Sean Sandborg and Alex Pevtsov on large-scale structures of active regions. He also worked with Alex Pevtsov on his paper of the emergence and submergence of a kinked omega-loop as an explanation of ASP vector magnetic field observations of an active region. He organized summer activities for a collaboration with Mona Hagyard at MSFC on use of her vector magnetograms for helicity studies. With Wuelser and Metcalf he contributed the section on magnetic reconnection for the Flare Dynamics Explorer SMEX proposal, and furnished other material to Bob Lin for the HESSI SMEX proposal. The final report of the Solar-B SDT was edited and forwarded to MSFC for production. Canfield also reviewed two manuscripts for ApJ and discussed separators and flares with DeMoulin. Research Scientist David McKenzie was very involved with YPOP this summer, but found time for research as well. Regarding period searches in SXT data, he performed some analysis suggested by Julia Saba to test for lower-confidence periods in regions of the loops other than those regions which showed periods at 99.5% confidence. He is currently in the "interpretation" phase. On another front, McKenzie has been examining some dense, very transient, brightenings seen near a flaring region on 93-Aug-21 -- most visible as fine structure in the leg of a sharply cusped loop. He has also been pursuing literature material and collateral data with regard to "zipper" arcades. Graduate student Brian Handy is beginning a project with Karel Page 8 Schrijver to understand x-ray bright points using MDI and EIT (and eventually TRACE) along with some 3-D B-field modelling. He also continues on the TRACE program. Mark Weber, another graduate student, has spent some time on a major revision of the SXT Chief Observer's Handbook, which is a compilation of the many issues with which a CO needs to be familiar. He also continues his work on studying coronal differential rotation with SXT data. The following papers by members of the MSU Solar Group were submitted or published. "On the Subphotospheric Origin of Coronal Electric Currents", A. A. Pevtsov, R. C. Canfield, and A. N. McClymont, ApJ, 481, 973 (1997). "What is the Spatial Relationship Between Hard X-Ray Footpoints and Vertical Electric Currents in Solar Flares?", J. Li, T. R. Metcalf, R. C. Canfield, J.-P. Wuelser, T. Kosugi, ApJ, 482, 490 (1997). "On the Origin of Helicity in Active Region Magnetic Fields", R. C. Canfield and A. A. Pevtsov, BAAS 29, 921, 1997. "Coronal Structure as a Diagnostic of the Solar Dynamo", S. I. Sandborgh, R. C. Canfield, and A. A. Pevtsov, BAAS 29, 888, 1997. "The Solar Flare Dynamics Imager: A Low-Cost Mission for This Solar Maximum", J.-P. Wuelser, M. E. Bruner, K. T. Strong, R. C. Canfield, J. L. Culhane, J. T. Mariska, R. Polidan, BAAS 29, 898, 1997. "NOAA 7926: A Kinked, Submerging Flux Loop?", A. A. Pevtsov, R. C. Canfield, BAAS 29, 900, 1997. "Conversion of YOHKOH X-ray Observations to Temperature & Spectral Radiance", L. W. Acton, D. Weston, M. E. Bruner, submitted to Solar Physics. MEETINGS: The 28th annual meeting of the Solar Physics Division of the American Astronomical Society took place at MSU on 27 June - 1 July. A great deal of positive feedback on the local arrangements and the scientific aspects of the conference have been received. By all accounts it was a complete success. Canfield and Pevtsov received formal AGU approval for a Chapman conference on "Magnetic Helicity in Laboratory and Space Plasmas", to be held next summer, and began working on funding and local organization. OUTREACH and SERVICE: Following the SPD Meeting, the YPOP Creative Design and Definition Team met for a half-day to synchronize their efforts and to start planning Page 9 for the future of YPOP. Immediately following THAT, we hosted the teachers and education specialists associated with the YPOP project in a 3-day workshop to design and begin writing lesson plans using solar data. McKenzie has since spent much of the month of July working with Tim Slater on preparing these lesson plans for use. Several hundred each of posters, lithographs, and business cards have been distributed to teachers. Acton and Canfield met with staffers of the Montana congressional delegation in June about the importance of MODA funding to MSU and about Solar-B. TRAVEL: During the bimester, Acton traveled to Washington, D.C. to participate in Yohkoh's presentation to the MODA Senior Review. All signs indicate that this mission was successful, and that the Yohkoh project will continue to experience a favorable funding environment in the United States. Weber spent some time in Japan assisting with Yohkoh operations. He returned in time for the SPD meeting. McKenzie and Charles Kankelborg attended the Fifth SoHO Workshop, in Oslo. Canfield participated in a meeting of the Solar Magnetism Initiative Committee, in Boulder. ======================================================================= Univ of Calif, Berkeley Activity Report for June 1997-July 1997 ======================================================================= (J. McTiernan) The Yohkoh work here at UCB in the past two months has concentrated on the calculation of Differential Emission Measures (DEM) for soft X-ray flares, using the SXT and BCS detectors. Results from this work were presented at the SPD meeting in Montana at the end of June. Since then, we have been improving the method to improve the quality of the DEM fits; originally out of a total of 93 flares in the original sample only two-thirds of the flares were acceptably fit. Now we can fit 83 of the original 93 flares. Those flares which are not fit well fall into two classes: (1) flares with saturation in the BCS channels, and (2) flares for which BCS, a full-sun instrument, sees a source not contained in the SXT PFI's. (The improvement in the method involved splitting the FeXXV channel of BCS into two components and using only the FeXXV resonance line to do the fit.) A paper is being written, and will be submitted for publication next month. Further improvements to the DEM calculation are planned, these include adding the SXV channel of BCS to the fits, after a suitable background-subtraction scheme is worked out, and also the inclusion of GOES and HXT-LO data to the DEM fits. (HXT-LO data can be used where it is clear from the time profiles that there is a gradual superhot component.) Page 10 ============================================================= Univ of Hawaii Activity Report for June 1997-July 1997 ============================================================= (B. LaBonte) Our activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition (including designated Yohkoh campaigns) at Mees, collaborative analysis of Yohkoh/Mees data, and preparation of manuscripts. Operational support for SXT was provided by Nitta at Mees and LaBonte in Manoa. Our colleagues Jiao and Mickey at Manoa, Canfield at Montana State University, Wuelser and Metcalf at Lockheed, and Hudson at Solar Physics Research Corporation aided in advice and oversight of Mees operations. The Haleakala Stokes Polarimeter was returned to operation after a long illness. The regular program of vector magnetogram surveys is underway. Observations of the new cycle active regions have dominated this interval. We supported the joint YOHKOH/SOHO Jets in Coronal holes campaign in July and the VLA observations on July 3. LaBonte, Mickey, and McClymont all attended the Solar Physics Division meeting in Bozeman, Montana and presented papers. There were at least 6 papers from outside the Hawaii group that used Mees data obtained under Yohkoh SXT collaborative observations. LaBonte is working with S. Hardy (University of Sydney) on the comparison of Mees vector magnetograms, Yohkoh SXT, H-alpha, and radio data for AR 7765 and AR 7790. The goal is a comparison of the observations with the predictions of various flare models with regard to the topology of electric current systems. LaBonte is working with J. Brosius (Hughes STX / NASA GSFC) on a study of AR 7563. The comparison of SERTS EUV data, VLA radio and Mees vector magnetograms will be used to understand the coronal magnetic fields and the role of electric currents in modifying the field from potential forms. In support of Mees Observatory planning, T. Metcalf had set up a Web page for tracking tropical storms. As of July, that page is used by the Federal Emergency Management Agency (FEMA) as the source of tropical storm tracks (www.fema.gov). Another benefit for the common man from diligence in solar observing operations. PUBLICATIONS AND PRESENTATIONS DURING JUNE AND JULY --------------------- PAPERS PRESENTED AT THE SOLAR PHYSICS DIVISION MEETING X-ray photon spectroscopy with the Yohkoh Soft X-ray telescope B. LaBonte (IfA, U. Hawaii), K. Reardon (Astron. Obs. Capodimonte) Page 11 Reconstruction of the Three-Dimensional Coronal Magnetic Field L. Jiao, A. N. McClymont (IfA, U. Hawaii), Z. Miki\'c (SAIC) Image Reconstruction for Stokes Polarimetry D. L. Mickey, B. J. LaBonte (U. Hawaii) ============================================================ Stanford Univ Activity Report for June 1997-July 1997 ============================================================ (M. Wheatland) The Yohkoh mission has produced the surprising observation that soft X-ray emission from the footpoints of flaring loops varies impulsively, matching the spiked time profile of hard X-ray emission. Proponents of the chromospheric evaporation model of flares have argued that the impulsive emission represents direct evidence for the start of the evaporative process, namely heating of the loop footpoints by the beam of energetic electrons responsible for the hard X-ray emission. However, there are difficulties with both possible interpretations of the soft X-ray emission in this scenario - as the low energy tail of non-thermal (thick-target) bremsstrahlung, or as thermal emission produced by plasma heated by the beam. Mike Wheatland, Vahe Petrosian (Stanford) and Jim McTiernan (Berkeley) have begun collaborating on an investigation of impulsive SXR footpoint emission, beginning with a re-examination of the Yohkoh observations. Peter Sturrock, working in collaboration with Jim Klimchuk, is pursuing a topic that Jim described at the Yohkoh Conference held in Bath in 1995. Soft X-ray emitting arcades are often observed to form and grow in the aftermath of coronal eruptions. They are generally interpreted as evidence for magnetic reconnection occurring at progressively greater heights along a vertical current sheet that is created by the eruption. Klimchuk compared the X-ray power budget of the January 26 1993 event with an estimate of the rate of release of magnetic energy based on a model of Wolfson, and found that the latter is larger than the former by a factor of order 100. However, it appears that the Wolfson model may greatly over-estimate the energy actually available to heat the trapped coronal gas. We have made a new estimate of the rate of release of magnetic energy in which we assume that the trapped coronal gas is heated only by the energy released below the X-type point where reconnection occurs. This reduces very considerably the rate of supply of energy to the trapped coronal gas. It remains to be seen whether this change alone will make it possible to reconcile the energy supply and the energy dissipation. It may be that part of the magnetic energy released during reconnection goes into propagating waves that carry part of the energy away from the coronal arcade. Sang-Hyun Kim, a summer student working with Peter Sturrock and Mike Wheatland, has started a project to look at coronal heating in extended, diffuse coronal regions. Sturrock and Wheatland (together with Loren Acton) Page 12 previously modeled the observed emission in these regions using an open field configuration, and a new attempt to reproduce the observed emission from a closed field configuration is needed. The goal of this work is to determine the location of energy deposition in these regions. Mike Wheatland has completed his work with Slava Glukhov towards the theory of the statistics of energy release in flares. The Rosner & Vaiana model for flares has been generalized to allow flares which do not deplete all free energy from the system, a step which overcomes a number of objections to the original model. A probability balance equation is obtained describing the free energy of an active region subject to a prescribed growth rate and a prescribed distribution of stochastic decay events. It is argued that the solution appropriate to flares must involve an energy-independent growth rate, and a power-law form for the distribution of decay events, which may be the result of an underlying avalanche process. The resulting model produces power-law flare frequency distributions over an arbitrary number of decades below a rollover set by the balance between growth and the rate of stochastic decay. There is a close correspondence between the resulting model and the avalanche model for flares. Papers submitted: Wheatland, M. S. & Glukhov, S. "A stochastic Model for the Energy of an Active Region," submitted to ApJ =========================================================================== Solar Physics Research Corp. Activity Report for June 1997-July 1997 =========================================================================== (Karen L. Harvey and Hugh S. Hudson) KAREN L. HARVEY: Activities for Harvey in the last two months include: (1) Analysis of XBPs observations obtained during a collaboration of several ground-based observatories and the Yohkoh SXT instrument, and SOHO in early April 1996. Several individuals are working on the reduction and analyses of the data on 12 April -- Harvey on the SXT data, Harvey and Penn on the He I spectral images, Tarbell and Saba on the MDI magnetograms, Moses on the EIT images, Fludra on the CDS images, and Hassler on the SUMER images. The results from the analysis of the data sets acquired on 12 April 1996 were presented as a poster paper at the 1997 SPD meeting in Bozeman. (2) The IDL programs to draw the irregular coronal hole boundaries on the NSO/KP He I 10830 spectroheliograms and its adaptation for the NSO/KP Carrington rotation He I 10830 maps was completed. This program is now being used routinely on the NSO/KP to prepare the preliminary coronal hole maps on a daily basis; these maps as gif images are located on the NSO archive Page 13 (argo.tuc.noao.edu: directory kpvt/daily/lowres). A program to do the final maps of coronal holes for the entire Yohkoh period will be begun within the next two months, providing information on the boundary locations and on the magnetic and He I 10830 characteristics of coronal holes during the decline of cycle 22. These data will be compared directly with the SXT observations of coronal holes. (3) Began a comparison with Hugh Hudson and Loren Acton of the filament cavities observed by the SXT on June 21, July 4, and July 18, 1997 with the NSO/KP photospheric and chromospheric magnetograms and He I 10830 spectroheliograms. Preliminary conclusion is that the boundaries of the filament channel observed in He I 10830 correspond to the edges of the X-ray cavity. (4) Preparation of NSO/KP full-disk magnetograms and He I 10830 spectroheliograms for SXT investigators for studies of the magnetic field and He I 10830 structures associated with X-ray structures. Planned Activities in Next Two Months Activities for August and September are to continue the analysis of the data from the several XBPs campaigns and the writing of the first in a series of planned papers on X-Ray Bright Points. Continue the analysis of the history of the activity complex 7958/7978, the evolution of the fields and connections, and the producing drafts of the next two papers planned on this work. Work also will be started on producing coronal hole maps for the Yohkoh period. HUGH S. HUDSON Activities in June and July Hudson attended the SPD meeting in Bozeman and presented a poster on the October 5 event (also discussed at the Oslo workshop by S. Watari, who is leading the study of this remarkable set of observations. Further plans for pursuing the analysis of SXT observations of CME-related events (e.g., dimming events) were discussed with Lemen and Webb. Other activities for Hudson included SXT support, specifically efforts to get the stray-light corrections improved via the use of the terminator images. He will also continue to work with organizational activities in preparation for the 2nd SOHO/Yohkoh CDAW, on active regions. Plans for August and September Hudson will try to make the Sept. 15 deadline with a Yohkoh paper for a GRL special issue on the CME of January 6, 1997. It will, of course, be a dull paper, since Yohkoh had little to work with and in general the CME had weak solar antecedents. But we will write a more general paper, including better- observed examples (including 7-Apr-97). Further related Page 14 work on CME counterparts, including 5-Oct-96 (Watari), 14-Apr-94 (Kahler), and various aspects of dimming (Lemen, Webb) will also be active items. Hudson would also like to follow up on the remarkable HXT observations reported by Sakao at Yoyogi and by Kosugi at Bozeman. These observations show that the footpoint separation in double-footpoint flares does not systematically vary in correlation with the flare energy release rate, as measured by the hard X-ray flux. This result conflicts directly with predictions from large-scale reconnection models and points to a need to identify flare energy, at least in the impulsive phase, with local magnetic storage. Papers published Bastian, T.S., Gary, D.E., Hurford, G.J., Hudson, H.S., Klimchuk, J.A., Petrosian, V., and White, S.M. "Broadband imaging spectroscopy with the Solar Radio Telescope", in Radio Emission from the Stars and the Sun, A.R. Taylor and J.M. Paredes (eds.), ASP Conference Series, Vol. 93, 430 (1996). Kamide, Y., McPherron, R.L., Gonzalez, W.D., Hamilton, D.C., Hudson, H.S., Joselyn, J.A., Kahler, S.W., Lyons, L.R., Lundstedt, H., and Szuszczewicz, E., "Magnetic storms: current understanding and outstanding problems", in Magnetic Storms, B.T. Tsurutani, W.D. Gonzalez, Y. Kamide, and J.K. Arballo (eds.), Geophysical Monograph 97, p. 1. Hudson, H. S., "The solar antecedents of geomagnetic storms", in Magnetic Storms, B. T. Tsurutani, W. D. Gonzalez, Y. Kamide, and J. K. Arballo (eds.), Geophysical Monograph 97, p. 35. Ueno, S., Mineshige, S., Negoro, H., Shibata, K., and Hudson, H.S., "Statistics of Fluctuations in the Solar Soft X-Ray Emission", Ap. J. 484, 920 (1997). Papers submitted Watari, S., Watanabe, T., Acton, L.W., and Hudson, H.S., "Limb events observed by Yohkoh and coronal mass ejections: a filamentary soft X-ray structure on 5 October 1996", 5th SOHO workshop, Oslo, June 1997. Page 15 ------------------------------------------------------------------------------- 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 August 1997 July 1997 |------------------------------- | 6. PERFORMING ORG | CODE: O/H1-12 -----------------------------------------------|------------------------------- 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 Palo Alto Research Labs B/252 |------------------------------- Solar & Astrophysics Laboratory O/H1-12 |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 | of July 1997 |------------------------------- |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 | 15 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office