Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for January 2000) 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 long awaited RFP for the continuation of operations and data analysis has finally arrived. Proposal activities have been initiated and the proposal should be submitted to NASA in a few weeks. SOLAR ACTIVITY The Sun started the new millennium quietly with activity at sub-C levels, though a few C-class flares were recorded early in January. As the month progressed, activity rose again, to meet the Flare Genesis telescope half-way. By mid-month there were 5 M-class flares. At the end of the millennium, a huge coronal hole was nearing disk center. Bearing in mind the "disappearing solar wind", we wondered (see last month's report) whether or not this equatorial coronal hole would again turn off the solar wind --- it did not. After mid-month, activity hovered near the GOES C1 level, with three M flares. Unfortunately, none of the M flares were in view of the Flare Genesis Experiment. January ended with active region maximum sunspot area 380 (NOAA 8824, one of the Flare Genesis targets) and activity dropping to extremely low levels. The GOES soft X-ray background was at mid-B level. There were no further GOES M-class flares at the end of the month, but many C-class flares, most at C1 level, The largest flare was a C6.8 flare. Page 2 CAMPAIGNS The Flare Genesis telescope was launched and Yohkoh and many observatories around the world concentrated on its targets. The first series of AR observations was probably not very productive in terms of major flares, but the active region (NOAA 8821) was not without microflare activity and (according to our images) had a rather curious sigmoidicity. The Flare Genesis telescope concluded its very successful flight with a cut-down and soft landing on the Ross Ice Shelf not too far from McMurdo. At the time of writing it seemed possible for the recovery of the data tapes, but not the gondola this season. SCIENCE T. Kosugi reported that the Dec. 28 1999 (01:00 UT) flare had an exceptionally hard HXT spectrum. SXT observed a mammoth loop filling and erupting. The HXT spectrum is consistent with a slope -1.4, indistinguishable from the magic slope -1.4 that would be produced by monoenergetic electrons at energies well above 33 keV. A harder spectrum from the bremsstrahlung mechanism, acting alone, is impossible from a theoretical point of view. Canfield worked with Hudson, Nitta, Alexander, LaBonte and others to identify, prepare, and co-align images for the Whole Sun Month 3 Flare Topology Working Group study of flares in AR 8668. At the workshop itself, it became clear that suitable data were available for three flares in this sigmoidal region, and an enthusiastic collaboration has begun that includes scientists from SXT, SOHO, TRACE, and a variety of GBOs. Fletcher worked with Daniel Brown from St. Andrews on applying his topological field models to the 3-may-99 TRACE/Yohkoh flare. With 7 photospheric field sources, they simulated the small-scale cancellation of flux and looked at the effect this would have on the coronal field (under all sorts of assumptions, like slow driving, potential field etc). They found that the field changes and location of heating at sites of spine, fan and separator reconnection predicted in his model looks rather like the TRACE and SXT observations. 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 January were 211095 accesses and 8690 Mbytes transferred. Page 3 YOHKOH OPERATIONS AND HEALTH Yohkoh and the SXT continue to function very well. Yohkoh survived Y2K without problems. The Japanese ground computer that archives Yohkoh data had some Y2K related problems but these were resolved in a few days. No data were lost and operations continued manually during this period. A few minor problems with the data reformatting software were also quickly resolved and no data were lost. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT Error 17-Jan-00 Pass 3: 000117-0723 Recovered in pass 4 SXT Error 30-Jan-00 Pass 1: 000130-0204 Recovered in pass 2 Page 4 Page 4 DATA FLOW Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Nov-97 506569 196854 2052111 425264 2477375 939076 27.24 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 6810 1892 27046 7357 34403 9970 22.47 Aug-98 5823 1960 22978 14126 37104 11167 23.13 Sep-98 6776 1432 21814 11626 33440 7753 18.82 Oct-98 6573 1901 23520 5198 28718 9220 24.30 Nov-98 6442 1695 25124 26948 52072 9920 16.00 Dec-98 5962 2005 21490 15770 37260 10561 22.08 Jan-99 5494 1825 20087 17620 37707 9622 20.33 Feb-99 5729 1525 30802 9798 40600 10630 20.75 Mar-99 6807 1844 24721 12354 37075 10064 21.35 Apr-99 6715 1371 25113 4179 29292 7791 21.01 May-99 6459 1807 35467 12092 47559 13757 22.44 Jun-99 6217 1915 23542 13051 36593 10086 21.61 Jul-99 5591 1745 20409 25747 46156 9670 17.32 Aug-99 6827 2503 21725 23361 45086 11844 20.80 Sep-99 5768 2011 21890 3434 25324 10846 29.99 Oct-99 5768 2308 22994 10487 33481 11517 25.59 Nov-99 7552 3425 20754 18772 39526 11974 23.25 Dec-99 7488 2791 22047 5354 27401 10663 28.01 Jan-00 82 -1 314 0 314 11 3.38 Total 667496 244095 2660911 714696 3375607 1187266 26.02 Number of Full Frame Images Received: 667496 Number of Observing Region Images Received: 3375607 Total: 4043103 Approximate Number of Shutter Moves/CCD Readouts: 6908853 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 (%) 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 57.01 993.7 215499 27493 21.4 N/A Aug-98 57.36 1006.7 217355 29544 20.9 N/A Sep-98 57.43 1009.5 218520 29683 20.9 N/A Oct-98 57.59 1015.3 220504 30221 21.3 N/A Nov-98 58.17 1037.0 223755 34614 22.5 / 2 23.4 N/A Dec-98 57.86 1025.5 221918 32420 23.8 N/A Jan-99 58.74 1058.6 227503 38238 23.1 N/A Feb-99 58.44 1047.4 224002 36198 23.2 N/A Mar-99 59.26 1078.1 227900 43051 21.7 N/A Apr-99 58.82 1061.4 225973 38963 23.8 / 1 21.4 N/A May-99 58.68 1056.4 225385 37726 21.6 N/A Jun-99 59.40 1083.0 230091 42440 22.0 N/A Jul-99 59.78 1097.5 231236 46337 23.8 / 1 20.6 N/A Aug-99 59.39 1083.0 229319 43067 21.7 N/A Sep-99 60.04 1107.3 231585 49084 21.8 N/A Oct-99 59.66 1092.9 229735 45263 22.8 N/A Nov-99 59.90 1102.0 231288 47102 23.0 N/A Dec-99 60.55 1126.3 233523 53920 22.5 / 2 25.3 N/A Jan-00 N/A N/A N/A N/A 22.5 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-JAN-00 and 31-JAN-00 HUDSON 1-JAN-00 * 17-JAN-00 17 28-JAN-00 31-JAN-00 * 4 (total of 21 days) MCKENZIE 16-JAN-00 31-JAN-00 * 16 (total of 16 days) ---------------------------------------------------------------- Grand Total of 37 days for 2 people NOTE: The "*" signifies travel that actually ends after 31-JAN-00 SXT Foreign Travel between 1-FEB-00 and 28-FEB-00 HUDSON 1-FEB-00 * 28-FEB-00 * 28 (total of 28 days) MCKENZIE 1-FEB-00 * 28-FEB-00 * 28 (total of 28 days) SHIRTS 21-FEB-00 28-FEB-00 * 8 (total of 8 days) ---------------------------------------------------------------- Grand Total of 64 days for 3 people NOTE: The "*" signifies travel that actually ends after 28-FEB-00 Respectfully submitted, Thomas R. Metcalf Frank Friedlaender Page 7 ======================================================================= Montana State University Activity Report for December 1999 - January 2000 ======================================================================= (L. Acton) OPERATIONS Canfield served as Yohkoh duty scientist at Mees from December 28th to January 3rd. McKenzie spent the second half of January at ISAS, serving as SXT Chief Observer. The major coordination task was with the Flare Genesis balloon experiment. Handy spent the month of January in an intensive Japanese language course at the Yamasa Institute in Okazaki, Japan. This in preparation for a larger role in SXT operations over the next couple of years. MEETINGS Canfield gave an invited talk on vector magnetic fields, sub-surface stresses and evolution of magnetic helicity at IAU Colloquium 179, CYCLICAL EVOLUTION OF SOLAR MAGNETIC FIELDS: ADVANCES IN THEORY AND OBSERVATIONS, December 13-16 1999, Kodaikanal, India. Pevtsov gave an invited talk on "Coronal structures as tracers of sub-surface processes" at the same meeting. Canfield also organized the "Flare Topology Working Group" at the Whole Sun Month 3 Workshop January 19-21i, 2000, Goddard Space Flight Center. Acton and Longcope attended the YOHKOH_8TH_ANNIVERSARY_SYMPOSIUM "Explosive Phenomena in Solar and Space Plasmas", December 6-8, 1999, in Sagamihara, Japan. Acton presented an invited paper entitled "The New Yohkoh Science Movie" which was co-authored with Davey, Freeland, Lemen and Metcalf. RESEARCH Canfield worked with Hudson, Nitta, Alexander, LaBonte and others to identify, prepare, and co-align images for the Whole Sun Month 3 Flare Topology Working Group study of flares in AR 8668. Suitable data were available for three flares in this sigmoidal region, and an enthusiastic collaboration has begun that includes scientists from SXT, SOHO, TRACE, and a variety of GBOs. Canfield, Hudson and Pevtsov finished a review article on sigmoids as precursors of solar eruptions, including sections on SXT observations, magnetic fields observations, and theory. Acton continued work with Davey, Freeland, Lemen and Metcalf on the new floating-point, fully-corrected SXT database of composite images. Final work on improved stray light correction and deconvolution of the point spread function received a boost by a 5 day visit to LMATC. Acton and Pevtsov are analyzing the 8+ year long SXT radiance database Page 8 in comparison to magnetic flux obtained from KPNO routine full disk magnetograms. EDUCATION Mark Weber successfully defended his Ph.D. dissertation, "Rotation Patterns in the Large-Scale Solar Corona" on 8 November 1999 under the supervision of Dana Longcope. He spent December and January cleaning up loose ends and helping Piet Martens edit the proceedings for IAU Symposium 195, HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSIONS FROM ASTROPHYSICAL PLASMAS. Angela Colman was honored with the MSU Alumni- Chamber of Commerce Award for Excellence, based on her outstanding record of academic achievement and community service. Canfield began working with two new students, Yuriko Yamazaki (ACE Language Institute) and Eric Erickson (Headwaters Academy), studying the relationship between sigmoids and signatures of eruptions in the SXT sfd movies on video disk. Piet Martens completed his graduate seminar "Solar & Stellar Winds" in early December. In January I started participating in a Webcast inter- academic "Space Mission Design Seminar", in which I will be teaching the session on "Mission Operations". OUTREACH Canfield continued to reformat the SXT Chief Observer's weekly reports at http://solar.physics.montana.edu/nuggets/ and mirror sites at Lockheed, ISAS, and MSSL. At MSU, the number of requests to this directory has grown rapidly, and is now second only to YPOP. Acton gave an after-dinner talk to the Montana Weed Control Association annual meeting in Great Falls, MT, on 12 January. With the new semester underway requests for school appearances are picking up with 3 presently booked for March and April. PUBLICATIONS Papers Submitted: ----------------- Canfield, R. C. "Sigmoids as Precursors of Solar Eruptions", Invited Paper for "Special Issue of IEEE Transactions on Plasma Science, 2000", submitted, 2000. Weber, M. and Martens, P. "Axial Fields in Quiescent Prominences" to ApJ Letters. McKenzie, D., "Supra-arcade Downflows in Long-Duration Solar Flare Events", to Solar Physics. Papers in Referee Process: -------------------------- E. R. Priest, C. R. Foley, J. Heyvaerts, T. D. Arber, J. L. Culhane, Page 9 and L. W. Acton, "A Method to Determine the Heating Mechanisms of the Solar Corona", to The Astrophysical Journal. Li, J., Kuhn, J., LaBonte, B., Raymond, J. C., and Acton, L., "Global Solar Corona Revealed by Time Series Observations", to The Astrophysical Journal. N.W. Griffiths, G.H. Fisher, D.T. Woods, L.W. Acton, and O.H.W. Siegmund, "Simultaneous SOHO and Yohkoh Observations of a Small Solar Active Region", to The Astrophysical Journal. ============================================================= Univ of Hawaii Activity Report for December 1999 - January 2000 ============================================================= (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 and Li in Manoa. Our colleagues Kupke 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. Weather at Mees was poor during most of this interval, with observations obtained on 67% of all possible days but often of limited duration. A major lightning storm in early December caused a number of instrument failures; the Stokes polarimeter is the last to be brought back to full operation. Y2K problems were restricted to quicklook data pipelines and did not prevent any observations. Mees observations supported the Flare Genesis balloon flight campaign to the extent that weather and instruments permitted. There are a number of days on which Mees got extended observations of the Flare Genesis region. LaBonte presented a paper "Electric Current Systems in Solar Active Regions" at the AGU meeting in December. Based on Mees observations with the IVM, he was able to detect the existence of small scale structuring of the field-aligned currents and their advection and evolution. This work is being developed into two papers, including a study of Mees/SXT selected flare events. LaBonte supported the Whole Sun Month workshop in January remotely by providing reductions of Mees data for the Sigmoids group. The direct interaction with the workshop participants was a good lesson in how the Page 10 participation in collaborative science efforts might be broadened without overloading the local facilities at the workshop site. In December 1999, Li gave 3 similar talks in 3 different places in Taiwan: Academic Sinica, Institute of Astronomy & Astrophysics, Tsing Hua University, and National Central University (NCU). The topic was "Solar Coronal Variation within a Solar Cycle". The talks were based on the time series observations on the corona using SXT, EIT and white light observations during solar minimum. She demonstrated the off-limb synoptic images made from SXT and EIT data, and explained the various features seen at corona such as coronal hole boundaries, polar plumes, high latitude streamers, coronal plasma temperatures and densities. On January, Li carried on the work on high latitude streamers using the data in 1996 and 1997. An ApJL is in preparation. Li has finished the model fittings and data reduction. So, a manuscript will be ready very soon. The background corona paper has been reviewed by a referee, and we have sent out the revised version to ApJ. ============================================================ Stanford Univ Activity Report for December 1999 - January 2000 ============================================================ (P. A. Sturrock) Peter continues to collaborate with Mike Wheatland (in Sydney) concerning a possible new approach to the CME problem. Many CMEs have the appearance of an explosive outburst of magnetic flux. One difficulty in understanding how this could happen is the so-called Aly-Sturrock theorem that the open field has the maximum energy of all field configurations with a specified distribution of normal field at the photosphere. However, the proof of this theorem rests implicitly on the assumption that all field lines penetrate the photosphere. We have realized that this need not be the case. For instance, we can conceive of a magnetic configuration in which a closed magnetic toroid, located at the equator, is held in place by an overlying field configuration. Field lines of the overlying field are rooted in the photosphere, but field lines in the toroid are not. Peter has proposed a specific model to test this hypothesis, and Mike is setting it up on a computer in Sydney. It will be interesting to see whether or not this configuration can have a total energy in excess of the energy of the corresponding open configuration. Peter has also begun to prepare an article presenting a "toy" version of the CME model we have in mind. It comprises a long but finite flux tube, anchored in the photosphere at both ends and held down by an overlying arcade. By using the Gold-Hoyle model as a guide, we find that, as the flux tube is progressively twisted, its outer diameter changes only slightly, but the magnetic energy builds up rapidly. We compare the energy of this configuration with the energy of the configuration produced if the arcade "ruptures" and allows the flux tube to penetrate into interplanetary space. The limiting state is one in which the flux Page 11 tube under the arcade is untwisted, and the flux that has broken through the arcade has made the transition to a fully open configuration. We can compare the energy of these two configurations. Depending on the length-to-radius ratio, it may require only a modest amount of twist for the initial configuration to have higher energy than the final configuration. In this case, the initial configuration may be metastable - stable for small perturbations but unstable for sufficiently large perturbations. This is the requirement for a system to exhibit an "explosive" onset of instability. It will be interesting to study the evolution of the helicity in this model, and to seek a comparison with observational data. Peter is also collaborating with Mike and with Jim McTiernan in Berkeley, concerning the optimization-function approach to the reconstruction of force-free magnetic field configurations from photospheric vector magnetograph data. The optimization-function method rests on the minimization of the integral of a sum of terms, each term being the square of the error in each relevant equation. One difficulty has been that it is necessary to specify (or guess) the magnetic field on the outer surfaces (away from the photosphere). However, we can generalize the optimization procedure by multiplying each term by a weighting function, and arranging that each such weighting function drops to zero at the outer surface of the domain. The boundary condition on that surface then becomes irrelevant, so that it is not necessary to specify the field on the outer surfaces. As another extension of the original procedure, we include a term that is the weighted square of the field strength on the outer surface. The effect of this term should be to seek a force-free field that matches the conditions on the photosphere and also falls off rapidly with distance from the source. Jim has now set up on his computer in Berkeley the program previously developed by Mike. There were one or two bugs, but these have now been eliminated. Jim has been able to reproduce Mike's results without weighting functions, and is now working on implementing the program that includes weighting functions. Publications Wolfson, R., Roald, C.B., Sturrock, .P.A., Lemen, J., & Shirts, P., 2000, Temperature Structure of the Quiet Corona: an SXT-SUMER Discrepancy," Ap..J., 529, 570 Roald, C.B., Sturrock, P.A., & Wolfson, R. 1999, The dependence of coronal heating on magnetic flux density in the photosphere, Ap J, in press. Wolfson, R., Roald, C.P., Sturrock, P.A., and Weber, M. 1999, Coronal X-ray Brightness and Photospheric Magnetic Field: A Study in Correlations, ApJ, in press Wheatland, M.S., Sturrock, P.A., & Roumeliotis, G. 1999, An Optimization Approach to Reconstructing Force-Free Fields, ApJ, submitted Page 12 =========================================================================== Solar Physics Research Corp. Activity Report for December 1999 - January 2000 =========================================================================== (K. Harvey and H. Hudson) KAREN L. HARVEY: Activities for December and January: (1) Continued with the comparison of coronal holes observed with the SXT and those determined using the NSO/KP He I 10830 spectroheliograms. The primary data are the synoptic rotation maps of both sets of observations, taking into account that these maps are constructed differently for the two data sets. Daily observations are also being used to determine in better detail the correspondence in the occurrence and boundaries of coronal holes observed in X-rays and the He I 10830 line, particularly as a function of disk position. As part of this study, we are also interested in the formation process of coronal holes, that is what new connections are established with the evolution of the magnetic fields of active regions both emerging and dispersing that lead to the formation of isolated, equatorial holes. Of note in this process may be the existence of linear zones which on either side the X-ray loops are directed in opposite directions, resembling a `hairpart'. (2) In a project with Terry Forbes, we are now in the process of identifying He I 10830 2-ribbon flares associated coronal holes and long-duration X-ray arcades change using the NSO/KP He I 10830 spectroheliograms. The period being surveyed extends from September 1991 to the present. Once this list is completed, a few events will be selected on the basis that (1) there is good temporal coverage by the SXT full-frame images, (2) the position of the event is on the solar disk at a location to minimize the geometrical effects of the line-of-sight magnetic flux measurements, and (3) we can establish fairly precisely the boundaries of the transient coronal holes using the SXT images and He I 10830 spectroheliograms. The objective of this study is to determine the reconnection rate as the open magnetic fields with the transient hole form into the closed loops of the arcade. (3) Continued with analysis of data taken in collaboration with NSO/KP, Yohkoh/SXT, SOHO, TRACE, BBSO during three observing campaigns: 18-23 September 1997, 4-6 May 1998, and 14-16 June 1998 to investigate the behavior of the coronal and chromospheric structures associated with cancellation/submergence sites of magnetic flux. For comparison, structures associated with the emergence of small bipoles. Intensity images from the SXT, TRACE and SOHO in several X-ray and EUV lines are being compared to pin point the height and temporal structure of the associated coronal/chromospheric bright points. (4) 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. Page 13 Planned Activities for February 2000 and March 2000: Continued analysis of (1) the association of coronal holes observed in He I 10830 spectroheliograms and the SXT full-frame images; (2) a study with T. Forbes of the reconnection rate of magnetic fields using long-duration arcade events/He I 10830 2-ribbon flares associated with X-ray dimming and transient coronal holes; (3) the XBP data collected during several observing campaigns, concentrating on the more recent runs, to derive the height and temporal structure of coronal and chromospheric bright points associated with magnetic flux cancellation and emergence; (4) updating the SXT publications list for refereed journals. HUGH S. HUDSON Activities for December and January: In December I attended the huge AGU Winter meeting, presenting a poster on the "big flare limit" (co-authors Alexander and Parnell). I also attended the Whole Sun Month workshop in January at GSFC, on the same trip presenting a seminar at NRL (see http://isass1.solar.isas.ac.jp/~hudson/talks/nrl.000118/talk.html). In the science area, I finished HESSI workshop papers (one with Karlicky, one with McKenzie) but alas did not get the major May 6 wave paper done. On the other hand, the Khan and Hudson paper on the homologous NS loop disappearances was accepted, as was an ApJ letter on implosions. New science during this period was a little bit lacking, since there are so many important things to work on. However one or two new ideas did surface, and as usual they are at least remembered as "science nuggets". One was the nagging question remaining from a major AGU press splash, namely an episode of "disappearing solar wind" in May 1999. At this time both the density and velocity at one AU dropped sharply, so that the ram pressure on the magnetosphere dropped by almost two orders of magnitude for about three days. What on the Sun could cause such an effect? So far as we can tell, nothing! I think that this important subject needs much more careful work than went into that science nugget (31-Dec-99). Unfortunately, I was able to convince myself that my idea for a soft X-ray reflection filter was not practical, and I'm about to drop it. It was fun doing a ray-tracing program, though. Plans for February and March 1. Finish the May 6 wave paper, hoping to get it out the door before the anniversary of its SXT science nugget (December 25). 2. Attend the MR2000 meeting in Tokyo, to present a further development of the "slow LDE" work. Page 14 3. Attend the ISTP workshop at GSFC in March, to present a paper on CMEs observed without coronagraphs. 4. Attend the Nishida memorial workshop, also at GSFC but in late March, to review Yohkoh evidence for magnetic reconnection. Should be fun. PUBLICATIONS: Papers Published Farnik, F., Svestka, Z., Karlicky, M., and Hudson, H.S., "Transequatorial Interconnecting Loops and Increase of their Length in the New Solar Cycle," Proc. 8th SOHO Workshop "Plasma Dynamics and Diagnostics in the Solar Transition Region and Corona," ESA SP-446, 305-310, 1999. Papers Accepted "Homologous Sudden Disappearances of Transequatorial Interconnecting Loops in the Solar Corona": J.I. Khan and H.S. Hudson (GRL) "Coronal Magnetic Implosions": H. S. Hudson (ApJ Letters) Papers Submitted "Global Coronal Waves: Implications for HESSI", H.S. Hudson and M. Karlicky (HESSI workshop proceedings) "Hard X-rays from 'Slow LDEs'", H.S. Hudson and D.E. McKenzie (HESSI workshop proceedings) "Coronal Magnetic Implosions," Yohkoh 8th anniversary symposium proceedings (extended abstract) =========================================================================== University of New Hampshire Activity Report for December 1999 - January 2000 =========================================================================== (T. Forbes) Work is now in progress in collaboration with Karen Harvey on using SXT observations and ground based magnetograms to measure the rate of reconnection in the aftermath of CMEs. By measuring the rate at which the magnetic flux opened by a CME disappears, one can determine the global rate of reconnection in webers per second (or maxwells per second in CGS units) as a function of time using. No specific model of the coronal magnetic field is needed using this approach. All that is required is the line-of-sight component of the field as obtained from a standard magnetogram and measurements of the surface area on the Sun corresponding to newly closed field lines. The latter can be determined by observing the disappearance of the temporary coronal hole formed by a Page 15 CME located near disk center. The mathematical formula which is used to determine the rate is derived and discussed in the publication "What Can We Learn about Reconnection from Coronal Mass Ejections?" by T.G. Forbes and J. Lin. This publication is now in press in the Journal of Atmospheric and Solar-Terrestrial Physics. Publications: Previously listed as in press: The effects of reconnection on the CME process, Lin, J., and T. G. Forbes, J. Geophys. Res., 105, 2375-2392, 2000. New publication not previously listed: What Can We Learn about Reconnection from Coronal Mass Ejections?, T.G. Forbes and J. Lin, J. Atmospheric Solar-Terrestrial Phys., in press, 2000. ======================================================================= University Of California Activity Report for December 1999 - January 2000 ======================================================================= (G. Fisher) Berkeley personnel involved with Yohkoh research over the past 2 months include George Fisher, D. Tod Woods, Neil W. Griffiths, Chris Johns-Krull, and Jim McTiernan. The paper ``Simultaneous SOHO and Yohkoh Observations of a Small Solar Active Region'' by Griffiths, Fisher, Woods, Acton and Siegmund has been accepted for publication by ApJ. Griffiths and Fisher, in collaboration with Metcalf (LMSAL) and Falconer (MSFC) are working to compute sheared neutral line lengths from the HSP magnetogram dataset for comparison with observed X-ray radiances and flaring energies/frequencies. We are collaborating with Falconer to make the method more accurate for magnetograms taken off disk-center. Page 16 ------------------------------------------------------------------------------- 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 February 2000 January 2000 |------------------------------- | 6. PERFORMING ORG | CODE: O/L9-41 -----------------------------------------------|------------------------------- 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/L9-41, 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: Larry Hill | of January 2000 |------------------------------- |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