Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for July 1998) OVERVIEW The YOHKOH Mission is a program of the Japanese Institute of Space and Astronautical Science (ISAS) with collaboration by the U. S. National Aeronautics and Space Administration and the U. K. Science and Engineering Research Council. The YOHKOH satellite was launched on 30 August 1991 from Kagoshima Space Center (KSC) in Japan. The purpose of this mission is to study high energy phenomena in solar flares and the Sun's corona. Under an international cooperative agreement, Lockheed Martin, under NASA contract, is providing a scientific investigation using the Soft X-ray Telescope (SXT), one of the primary experiments of the mission. The SXT was developed at the Lockheed Martin Solar and Astrophysics Laboratory in cooperation with the National Astronomical Observatory of Japan, and the Institute for Astronomy of the University of Tokyo. MAJOR PROGRAMMATIC ACTIVITIES IN THE MONTH The program continues in a productive and cost effective manner. Computer upgrades are currently being performed in Japan. Yohkoh is still the standard against which newer programs are being measured. << Solar Activity >> In early July, solar activity remained moderate. The chief active region, 8253, reached a maximum area of about 230 millionths. Activity diminished in mid-month, with only a few C flares. The chief active region, 8263, reached a maximum area of about 200 millionths. We very likely observed lots of microflares in conjunction with TRACE. An M4.6 flare occurred on 14 July and Yohkoh observed the decay phase of this event. In late July the GOES level remained between B and C and the science planning emphasized active-region structure. Active region belts were seen in both the northern and southern hemispheres, at similar latitudes, but none of the regions produced major flares. Several loop brightenings were seen in AR 8282, which was the target region of the Hida campaign. << Campaigns >> In the first half of the month, there were no organized campaigns, but SXT followed TRACE active-region studies on NOAA 8253. We are looking for ways to be more helpful for TRACE planning in the absence (temporary, we hope) of SOHO whole-Sun images. At the end of July, the Hida campaign resumed. We coordinated with TRACE and Hida Observatory to observe signatures of emerging flux. The weather at Hida Page 2 was not cooperative, but this coordination continues through 8-Aug-98. << Science >> Sam Freeland has spotted one of the most remarkable solar phenomena Yohkoh SXT has seen. It consists of three simultaneous and extremely similar X-ray jets, see http://www.lmsal.com/YPOP/ProjectionRoom/Weekly/980711.html. At about 12:57 UT on July 7, three curved jets appeared. The lightcurves peak simultaneously within the sampling, a few minutes. Jet "A" was at (S21,E45); "B" at (N12,E31), and "C" at about (N17,W13) in the leading part of NOAA AR 8264, which had been producing many jets. These jets are simultaneous, curved in curiously similar and symmetrical ways, and have about the same lengths, but one of them seems to have excited a long-lived loop. Well-developed jets of this quality do not happen too often. If we guess one per week, and claim that the simultaneity is within five minutes, there would be a probability of about .0004 for two such events to occur together. Thus in seven years (350 weeks) of Yohkoh data, we actually would have a fairly high probability - 15% - of seeing a pair of events. But the probability drops to 6 x 10^(-5) for three at once. The probability is a lot smaller for such a beautiful match in properties, of course. Of course this is a posteriori and one will never know until more examples are found, but it seems just too extraordinary to be a coincidence. It seems, on the basis of this one observation, that it would be highly unlikely for emerging flux to arrive simultaneously at positions so far removed. The limit imposed on the exciter (trigger) speed would be >1000 km/s for a five-minute time difference. This could only be coronal in origin, not sub-photospheric. This seems to rule out one of the most popular jet models. But what bizarre MHD effect in the global corona could suddenly make up its mind to pluck three beautiful jets out of the photosphere at once? And another question - how do the well-defined curvatures of the jet structures fit into the quadrupolar structure of the global corona so well defined by the late lamented LASCO? << Public Use of SXT Images >> We are continuing to make Yohkoh/SXT images available for a variety of uses. Efforts continue to make selected images available on the LMSAL SXT WWW homepage (http://www.lmsal.com/SXT/). We receive requests for the Yohkoh posters (#2 and #3) by way of the form on the SXT homepage. Currently we receive requests via our homepage at the rate of 2 or 3 per day. The WEB access statistics in July were 71133 accesses and 3014 Mbytes transferred. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT Bitmap error 01-July-98 Pass 1: 980701-1030 Page 3 recovered in the same pass. SXT Bitmap error 30-July-98 Pass 1: 980730-1548 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-96 372066 159781 1551351 363350 1914701 770030 28.60 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 7671 1557 25649 1396 27045 8045 22.93 Jul-97 8614 1385 32503 431 32934 6559 16.61 Aug-97 7316 987 23136 3519 26655 4990 15.77 Sep-97 7051 1479 33646 9596 43242 8887 17.05 Oct-97 7023 1134 26813 1827 28640 6043 17.42 Nov-97 6691 1376 26297 15306 41603 7131 14.63 Dec-97 6806 1013 28472 2136 30608 5263 14.67 Jan-98 5715 1803 23479 3232 26711 9918 27.08 Feb-98 6606 1644 25257 3606 28863 8989 23.75 Mar-98 6043 2056 23029 10399 33428 10939 24.66 Apr-98 6537 1103 22656 8087 30743 6339 17.09 May-98 7569 1838 28292 19018 47310 9868 17.26 Jun-98 6463 1638 24990 5618 30608 9051 22.82 Jul-98 2314 901 8531 2007 10538 4342 29.18 Aug-98 0 0 0 0 0 0 NaNQ Total 554622 208850 2236817 479367 2716184 1003785 26.98 Number of Full Frame Images Received: 554622 Number of Observing Region Images Received: 2716184 Total: 3270806 Approximate Number of Shutter Moves/CCD Readouts: 5687645 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-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 53.71 869.8 182715 14910 19.8 N/A Jul-97 54.44 897.3 184518 20173 22.5 / 2 21.1 N/A Aug-97 54.06 883.1 188485 15549 20.1 N/A Sep-97 54.77 909.7 196501 17757 21.0 N/A Oct-97 54.85 912.8 198157 17857 21.5 N/A Nov-97 55.17 924.8 202153 18993 22.5 / 2 23.1 N/A Dec-97 55.51 937.6 206194 20219 21.9 N/A Jan-98 56.06 958.0 212189 22121 23.9 N/A Feb-98 55.94 953.7 209254 22122 23.8 / 2 22.6 N/A Mar-98 56.29 966.6 213519 23249 21.8 N/A Apr-98 56.44 972.1 214676 23890 20.8 N/A May-98 56.90 989.4 215651 26905 21.4 N/A Jun-98 57.11 997.5 216285 28223 20.1 N/A Jul-98 56.77 984.5 214236 26016 23.1 N/A Aug-98 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-98 and 31-JUL-98 HUDSON 1-JUL-98 * 12-JUL-98 12 18-JUL-98 25-JUL-98 8 (total of 20 days) NITTA 28-JUL-98 31-JUL-98 * 4 (total of 4 days) SHIRTS 1-JUL-98 31-JUL-98 * 31 (total of 31 days) SLATER 1-JUL-98 31-JUL-98 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 86 days for 4 people NOTE: The "*" signifies travel that actually ends after 31-JUL-98 SXT Foreign Travel between 1-AUG-98 and 31-AUG-98 ALEXANDER 3-AUG-98 28-AUG-98 26 (total of 26 days) HUDSON 1-AUG-98 6-AUG-98 6 16-AUG-98 31-AUG-98 * 16 (total of 22 days) NITTA 1-AUG-98 * 8-AUG-98 8 27-AUG-98 31-AUG-98 * 5 (total of 13 days) SHIRTS 1-AUG-98 * 12-AUG-98 12 (total of 12 days) SLATER 1-AUG-98 * 10-AUG-98 10 (total of 10 days) ---------------------------------------------------------------- Grand Total of 83 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-AUG-98 Respectfully submitted, Thomas R. Metcalf Frank M. Friedlaender Page 7 ================================================================= Montana State Univ Activity Report for June 1998-July 1998 ================================================================= (D. McKenzie) The best event of the period was Brian Handy's successful thesis defense on 12 June. Dr. Handy has accepted a post-doctoral appointment at MSU. OPERATIONS: McKenzie spent June at ISAS, wrote explanatory material and edited programs to make version 4.1 of the Chief Observer handbook. Also contributed programs for use in Yohkoh observation-planning. Using models and software from MSFC, worked to estimate likelihood that Yohkoh will be struck by a Leonid meteoroid. Based on the current model, risk appears to be small but nonzero. Kankelborg devoted time to consideration of how to do science planning for SXT and TRACE in the absence of SOHO data. We are learning to coordinate more effectively between the remaining space-based missions and ground-based observers. SCIENCE: Acton began a new analysis project with Jing Li at SAO, again combining UVCS and Yohkoh data on a limb observation. McKenzie continued analysis of loop expansion/motion in concurrent CDS/SXT data from Feb 11-12; also examined data from 11-jun-98 M flare, expansion of over-the-limb arcade with ejecta and spiky tops. Canfield worked with Hudson on a paper on CMEs and sigmoids. Davey continued work on a CII paper in collaboration with colleagues at UCL, England. Weber has been concentrating on reading in regards to a thesis question, and has also continued learning about methods of global modeling of the solar magnetosphere. Kankelborg, with Longcope, outlined a coronal heating paper; and with Canfield did some analysis on JOP 80 data for a flare study -- difference images, light curves and the like. TALKS and PUBLIC OUTREACH: Talk: "Helicity and Reconnection in the Solar Corona", Richard C. Canfield, Chapman Conference on Magnetic Helicity in Laboratory and Space Plasmas, Boulder, July 1998. In July McKenzie supervised a student from the American Indian Research Opportunities Montana Apprenticeship Program. High school student Samantha Allen joined the MSU solar group for three weeks, and did some statistical work on the use of sigmoid morphology of active regions as a predictor of eruption likelihood. MEETINGS: Canfield and Pevtsov organized the Chapman Conference on Magnetic Helicity in Laboratory and Space Plasmas, held in Boulder in July. Several members of the MSU team attended the meeting. The meeting was attended by Page 8 about 100 specialists in this subject from all over the world. PROPOSALS: Acton prepared an SXT/Yohkoh proposal to L-M for additional theoretical work. The whole team spent quite a lot of time working on proposals for Solar-B. GUESTS: Prof. Eric Priest of St. Andrew's Univ., St. Andrew's, Scotland, arrived with his family for a one month visit on 20 June. Dr. Karel Schrijver visited for a long weekend beginning 10 July. COMPUTING EQUIPMENT: Davey spent some time configuring our new Dec Alpha. This machine (dual processor 533 MHz / 2 Gig of memory) probably represents a significant increase in computing power in Montana ! This machine will become the central machine of the solar physics cluster. PUBLICATIONS: Acton spent time working on a paper, "Super-X: A Soft X-ray Telescope for Solar-B" for SPIE. Additionally, the following papers were submitted and/or accepted. Manuscripts accepted: "UV Observations with the Transition Region and Coronal Explorer", Handy, Bruner, Tarbell, Title, Wolfson, Laforge & Oliver; accepted for publication in Solar Physics. "Data Analysis with the SolarSoft System", Freeland & Handy; accepted for publication in Solar Physics. "A Space-Age Portrait of the Active Sun", D.E.McKenzie, T.F.Slater, accepted by "The Physics Teacher" for publication in October. "A Stable Filament Cavity with a Hot Core", H.S.Hudson, L.W.Acton, K.L.Harvey, D.E.McKenzie, accepted by ApJ Letters. Manuscripts submitted: "Bringing Physics of the Sun to the Public", T.F.Slater, M.B.Larson, D.E.McKenzie, submitted to "Technological Horizons in Education (THE) Special Issue on: Partnerships: Industry/Education Success Stories". OTHER SERVICE: Canfield worked on hire of Asst/Associate Research Professor, and refereed two proposals. ============================================================= Page 9 Univ of Hawaii Activity Report for June 1998-July 1998 ============================================================= (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 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. Weather during this interval has been good, with regular observations on > 80% of all workdays. All instruments are working well. The IVM is regularly taking magnetogram movies throughout the observing day. Planning for Whole Sun Month, now Fortnight, was carried out. The Imaging Vector Magnetograph will be set to observe the Na I D line to measure chromospheric vector magnetic fields. The Haleakala Stokes Polarimeter will continue to observe photospheric fields. LaBonte has begun work on the analysis of AR8210, a flare productive region that appeared at the end of April. This region produced numerous large flares and CMEs; preliminary study of the IVM movies show large-scale advection of the magnetic field which are either vortical or helical, depending on the relative importance of transverse flows and magnetic buoyancy. PAPERS PRESENTED: Optical Proxies for High Energy Emissions from Stars. 1998. Blais, K. A., and LaBonte, B. J.: B.A.A.S., 30, 845. June 1998 AAS Meeting, San Diego. PAPERS PUBLISHED: Probing the Subsurface Structure of Active Regions with Phase Information in Acoustic Imaging. 1998. Chen, H.-R., Chou, D.-Y., Chang, H.-K., Sun, M.-T., Yeh, S.-J., LaBonte, B., and the TON Team: Astrophys. J., 501, L139. PAPERS USING MEES COORDINATED OBSERVATIONS: Coronal Currents, Magnetic Fields, and Heating in a Solar Active Region J. Lee, A. N. McClymont, Z. Mikic, S. M. White, & M. R. Kundu 1998 July 10, Astrophys. J., V. 501, p.853. Page 10 ============================================================ Stanford Univ Activity Report for June 1998-July 1998 ============================================================ (P. Sturrock) We announce with pleasure that Colin Roald, recently at Rochester University, joined our group in July. We are making plans to investigate the behavior of thin flux tubes in the solar corona. In the coronal-heating model that Peter is developing, reconnection at the chromospheric level leads to the creation of new flux tubes in the corona, in a state of transverse oscillation. It is believed that sound waves generated by these oscillating flux tubes is an important contributor to coronal heating. Colin will undertake to calculate the dynamical properties of these oscillating flux tubes. How much kinetic energy can be stored in such flux tubes? Is the kinetic energy lost only by sound waves? Do the oscillations heat gas inside the tube as well as outside the tube? A convenient approach to this problem is to use the equations for curved thin flux tubes that have been developed by Spruit and others for application to flux tubes in the convection zone. We intend also to review data on coronal loops. It has been a puzzle that loops appear to have constant cross section, even when they extend to considerable height. If coronal loops outline thin flux tubes, one would expect the thickness to be larger at greater height. Our initial analysis shows that, if the tubes are in fact in a state of oscillation, the amplitude will be almost independent of position along the tube. In this case, the coronal loop could appear to have constant thickness. This possibility can be examined in more detail by means of the model we are developing. Sang Hyun Kim has drafted a report summarizing his analysis of loop-like structures in one of the diffuse coronal regions previously analyzed by Mike Wheatland and Peter in their collaboration with Loren Acton. Taking into account the energy equation, Sang Hyun has considered a number of models of the loop with different geometries. He gets the best fit for a model due to an assumed line dipole, for which energy is injected uniformly along the length of the loop. With continued support from Mike Wheatland in Sydney, Colin will be continuing our collaborative investigation with Sasha Kosovichev and Rick Bogart of the Stanford University SOHO/MDI team concerning the relationship between the soft X-ray luminosity of the solar corona and the photospheric magnetic flux. For a 3 or 4 month period, Sasha and Rick will produce daily averages of the absolute value of the magnetic field histogram for a small region at Sun center. Mike and Colin will produce daily average values of the X-ray flux, as measured by Yohkoh, over the same region for the same time interval. The goal is to extract from these data sets an improved scaling relationship between the X-ray flux and the average field strength, for comparison with various models of coronal heating. Article accepted for publication: The Waiting-Time Distribution of Solar Flare Hard X-Ray Bursts, by M. S. Wheatland, P. A. Sturrock, and J. M. McTiernan (December 10, 1998 issue of ApJ, Vol. 509 #1) Page 11 =========================================================================== Solar Physics Research Corp. Activity Report for June 1998-July 1998 =========================================================================== (Karen L. Harvey and Hugh S. Hudson) KAREN L. HARVEY: Activities for June and July: (1) Prepared results of study with Hugh Hudson on the evolution of the magnetic field and coronal holes associated with the active region complex which occurred during several rotations in the summer 1996 for a paper presented at the COSPAR meeting in Nagoya. (2) Collaboration between NSO/KP, Yohkoh/SXT, SOHO, TRACE, BBSO during an observing program 14-17 June 1998 to study if magnetic flux in quiet sun canceling bipoles is submerging below the photosphere or continuing to rise through the photosphere. The magnetic field observations at NSO/KP were made simultaneously in two lines: the Ca II 8542 chromospheric line and the Fe I 8538 photospheric line. The separation in height between the two lines, about 2000 km, should be sufficient to determine flux differences at these two levels of the atmosphere as a function of time. The intensity and velocity data obtained in other lines and spectral regions provides the needed input on the response of the chromosphere and corona to the cancellation of magnetic flux. (3) Preparation of NSO/KP full-disk magnetograms and He I 10830 spectro- heliograms for SXT investigators for studies of the magnetic field and He I 10830 structures associated with X-ray structures. Planned Activities for August and September: The analysis of the magnetic fields and coronal holes related to the 1996 activity complex and the large scale field patterns will continue and will be written up for publication. This includes determining the how the coronal connections, based on the SXT data, to the photospheric magnetic field developed over several months as this complex and the new cycle regions evolved. An initial paper will be written for the COSPAR meeting. An investigation of the magnetic field evolution around the filament channel observed as a coronal cavity in 1997 will continue. The analysis of the XBP data collected during several observing campaigns. In particular, we are concentrating on the more recent runs with the computer intensive reduction of the zonal scans (line profiles) in the Ca II 8542 and Fe I 8538 lines made during the 4-6 May and very successful 14-17 June 1998 runs. Papers Accepted Hudson, H. S., Acton, L. W., Harvey, K. L., and McKenzie, D. E.," A stable filament cavity with a hot core," Ap J Page 12 HUGH S. HUDSON Activities in June and July Hudson presented several items at the COSPAR meeting in Nagoya. The best-received of them seems to have been the paper with Schwenn following up on the filament-channel observations. The ApJ Letter on this subject was accepted, incidentally. Other COSPAR presentations were not so successful, not counting the K. Harvey paper which was extremely well prepared, and one of the poster presentations (on the total-irradiance effects of network activity detectable in X-rays) had to be dropped for lack of time. Visits to ISAS by George Simnett and Dave Webb resulted in quite a bit of new CME-related work. One of the more exciting things was a LASCO movie Simnett showed, in which a clear inward motion - starting at about 4 solar radii projected - can be measured. Astounding even if not an SXT result! On the SXT side, Webb and Hudson discovered something quite interesting in the October 5, 1996 CME event. Please refer to the science nugget for details (http://www.solar.isas.ac.jp/sxt_co/index.html). Plans for August and September More CME work for Hudson, including several projects related to helicity and eruptions. We really believe that we have a handle on a predictions tool here, a result that has been building up for some time. The key paper on this subject is now in preparation by Dick Canfield, surveying the eruptive properties of active regions in 1997. Other activities will probably include HXT data analysis to follow up on the ideas presented at COSPAR by Hudson and Khan, namely a characterization of flare energy release via hard X-ray footpoint motions. There are exciting observations reported by Sato on the X9 flare of Nov. 6, 1997, and the HXT software is in such good shape now that even better examples (ones for which the magnetic-field data can be more decisive) are available for analysis. A major operations-related task should be tackled: the increasing weakness of the HXA component of the Yohkoh aspect solution. Hudson will work on HXA scan telemetry as a possible alternative to the present scheme, which uses the more frequently sampled threshold data. Papers Submitted Fisher, B. M., Hudson, H. S., and Jones, B., 1998, "A Search for Jovian p-mode Oscillations and Observations of Tropospheric Longitudinal Structures", Icarus Papers Accepted Hudson, H. S., Acton, L. W., Harvey, K. L., and McKenzie, D. E.," A Stable Filament Cavity with a Hot Core", ApJ Page 13 Gopalswamy, N., Hanaoka, Y., Kosugi, T., Lepping, R. H., Steinberg, J. T., Plunkett, S., Howard, R. A., Thompson, B. J., Gurman, J., Ho, G., Nitta, N., and Hudson, H. S., 1998, "On the Relationship between Coronal Mass Ejections and Magnetic Clouds", GRL =========================================================================== Naval Research Laboratory Activity Report for June 1998-July 1998 =========================================================================== (J. Lean) In July 1998, NRL received initial funding for our participation in the Yohkoh SXT Mission to Solar Maximum program.There are two main components of NRL's proposed effort. The goal of the work by Lean, Wang and Mariska has as its focus the global variability of the corona, both in comparison with other global radiation observations such as from UARS, and as simulated using ground-based solar magnetograms. Using Yi- Ming's potential field extrapolation model we plan to simulate the full disk solar corona for the duration of the SXT observations. This approach requires assumptions about the brightness of coronal emission that is associated with magnetic fields lines of different strengths. Wang et al (Ap. J. 1997) used a similar approach recently to model LASCO coronal greenline images. We have adapted these procedures for the SXT simulations and have begun by comparing six different days. Since the difficulties in simulating the corona with potential field extrapolations is well known, it is not surprising that agreement between the SXT observations and initial modelled images is only fair. We will use comparisons of the observed and modelled global coronal output as a guide to refine and adjust the model assumptions. We are actively seeking a postdoctoral researcher (without success thus far) to participate in this work. Jim Klimchuk's work focuses on the development of Earthward -directed CMEs and the prediction of their geoeffectiveness. He has also begun to plan the Yohkoh review paper he will write with Saku Tsuneta for Reviews of Geophysics. He has collected a list of references and has started to think about how his sections will be organized. His contribution to this review will emphasize coronal heating and coronal =========================================================================== University of New Hampshire Activity Report for June 1998-July 1998 =========================================================================== (T. Forbes) T. Forbes met with Hugh Hudson and Allen McAllister in preparation for the start of a new study on magnetic shrinkage. He also plans to get Acton involved in this, hopefully, in a few months time. The proposed paper is closely related to the paper by Hiei and Hundhausen (Hiei, E. & Hundhausen, A. J. (1996) Development of X-ray helmet structure, In Magnetodynamic Phenomena in the Solar Atmosphere, IAU Colloq. 153 (eds. Y. Uchida, Page 14 T. Kosugi, H. S. Hudson) pp. 125-126. Kluwer, Dordrecht) except that it will include several events and an extensive effort to develop an analytical model to quantitatively relate the observation of the rise rate of the X-ray loop system to the downward motion of condensation features. 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 1998 July 1998 |------------------------------- | 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 Martin Missiles and Space |------------------------------- Advanced Technology Center, O/H1-12, B/252 |11. CONTRACT OR GRANT NO. 3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 40801 -----------------------------------------------|------------------------------- 12. SPONSORING AGENCY NAME AND ADDRESS |13. TYPE OF REPORT AND Marshall Space Flight Center (Explorer Program)| PERIOD COVERED Huntsville Alabama 35812 | Progress report for the month Contact: John Owens | of July 1998 |------------------------------- |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