Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-00119) (for September 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 Activities on the new contract are progressing well. We recently hired Dr. Aki Takeda to work in Japan supporting SXT operations and we welcome her aboard. We are also in the process of hiring Dr. Janos Bartos to work in Japan on computer system maintenance. These personnel changes will make the operations at ISAS more efficient. Finally, we are working on plans for a scientific symposium to celebrate the 10th anniversary of the Yohkoh launch next year. SOLAR ACTIVITY In early September, solar activity remained low. There were M-class flares on September 4 and 9. Towards the middle of September, solar activity remained low but activity surged briefly around the growth of AR 9165, for which there was an early warning from P. McIntosh. A total of 5 M-class flares occurred during 14-16 September. Except for the first one, which came from AR 9166 (the target region of JOP 126), these flares were all produced in the rapidly growing region AR 9165. In late September, solar activity was moderate with two M class flares and several C-class flares. The most spectacular event was an M5.1 LDE in NOAA 9165 on 19 September. Unfortunately, this flare occurred during Yohkoh night. The other event was an M4.3 flare in NOAA 9166 on 24 September which Yohkoh observed. At the end of September, activity picked up with one X-class flare, four M-class flares, and multiple C-class flares. The X-class flare was X1.2 Page 2 on 30 September and the M-class flares were M1.8 on 25 September, and M1.0 and M1.8 flares on 30 September, all observed by Yohkoh. An M3.4 flare on 25 September occurred during Yohkoh night, unfortunately. The X-class flare did not have a CME associated with it which is somewhat unusual. This event came from AR 9169, which peaked out at an amazing 2160 millionths sunspot area but didn't make many flares until (of course) it was very near and then behind the W limb. CAMPAIGNS We supported the TXI rocket (SAO tunable X-ray imager). It flew on schedule, but its SPARCS system (pointing) failed so there were no data. We also supported JOP126 studying coronal loop temperature structure. For this campaign we've observed strip images (1024x256) at full resolution. We also supported JOP 104, SUMER observations of jets. However, Yohkoh has not been able to help much because of the pointing requirements. SCIENCE SXT has, over the last two months, been experimenting with a 2x2 flare table, including a McKenzie special deep exposure. This ingenious technique allows us to get large dynamic range, so we are now applying it to get good information about scattering wings. The flare table has been returned to its previous state (8 filter slots, 16-sec nominal cadence) with the addition of a Be overexposure. The general subject of wavelength-dependent scattering wings suddenly seems very important because of thesis work on SXT temperature maps under way at ISAS in particular. We feel that the 2x2 experiment was quite successful (see the various science nuggets describing individual events, both eruptive and non-eruptive). The Yohkoh Hard X-Ray Telescope recently produced a remarkable discovery -- the first observation of flare ribbons in hard X-rays. Although such bright ribbons have often been observed in visible light, this observation in hard X-rays gives new evidence for particle acceleration in 3D. The HXT images from the Bastille Day flare (July 14, 2000) show directly, for the first time, that non-thermal electrons excite flare ribbons. If HXT had adequate resolution, we think that a flashing and twinkling array of tiny, intense hard X-ray sources would flicker along the ribbons as the point of flare energy release propagated through its coronal reservoir. Even with data of this resolution, we look keenly forward to matching features with soft X-ray and EUV observations. This flare almost surely gives us a chance to discuss some of flare theory's hard questions - what is the 3D coronal structure, and how does its evolution accelerate non-thermal particles? Page 3 PUBLICATIONS Submitted: Watanabe, T., Sterling, A. C., Hudson, H. S., and Harra, L. K., "Energetics of an Active Region Observed from Helium-Like Sulphur Ions": ApJ (September 2000). Accepted: "On the Evolution of the Solar Photospheric and Coronal Magnetic Fields", Handy, B. N. & Schrijver, C. J., Accepted by ApJ. Sturrock, P.A., Weber, M., Wheatland, M.S., & Wolfson, R. 2000, Metastable magnetic configurations and their significance for coronal mass ejections. ApJ, in press. Wolfson, R., Roald, C.P., Sturrock, P.A., Lemen, J., & Shirts, P. 2000, Temperature Structure of the Quiet Corona: an SXT-SUMER Discrepancy, ApJ, in press. McKenzie, D. D., and Hudson, H. S., "Downflows and structures above LDE Arcades: Possible Signatures of reconnection?": EPS, September 2000. Hudson, H. S., and McKenzie, D. E., "Hard X-rays from Slow Flares": EPS, September 2000. Published: Nature of Solar Polar Rays 2000. Li, J., Jewitt, D., LaBonte, B. J. Astrophys. J., 539, L67. Roald, C.B., Sturrock, P.A., Wolfson, R. 2000, Coronal Heating: Energy Release Associated with Chromospheric Magnetic Reconnec- tion, ApJ, 538, 960. Wheatland, M.S., Sturrock, P.A., & Roumeliotis, G. 1999, An op- timization approach to reconstructing force-free fields, ApJ, 540, 1150. 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, 539, 995. Harvey, K. L., and Hudson, H. S., "Solar Activity and the Formation of Coronal Holes": Adv. Space Res. 25(9), 1,735 (2000). Sterling, A. C., Hudson, H. S., Thompson, B. J., and Zarro, D. M., "Yohkoh SXT and SOHO EIT Observations of Sigmoid-to-Arcade Evolution of Structures Associated with Halo Coronal Mass Ejections": ApJ 532, 628 (2000). Page 4 Harvey, K. L., and Hudson, H. S., "Solar Activity and the Formation of Coronal holes," Adv. Space Res. 25(9), 1,735 (2000). Gopalswamy, N., Hanaoka, Y., and Hudson, H. S., "Structure and Dynamics of the Corona Surrounding an Eruptive Prominence": Adv. Space Res. 25(9), 1,851 (2000). Hudson, H., and Schwenn, R., "Hot Cores in Coronal Filament Cavities": Adv. Space Res. 25(9), 1,859 (2000). 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 September were 127908 accesses and 6522 Mbytes transferred for the SXT website and 185505 accesses and 4047 Mbytes transferred for the YPOP website. The YPOP sundial lesson was used by a firm from Hollidaysburg, Pennsylvania to construct a sundial for a local park. To see images of the sundial visit http://solar.physics.montana.edu/YPOP/Classroom/Lessons/Sundials/ParkDial.html 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: Bit Map Error 19-Sep-00 Pass 1: 000919-0619 Recovered in the same pass Bit Map Error 27-Sep-00 Pass 4: 000927-0721 Recovered in the same pass Page 5 DATA FLOW Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jul-98 559118 209841 2255332 484717 2740049 1009413 26.66 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 5426 1736 19802 4040 23842 8958 27.31 Feb-00 6533 2052 21801 7017 28818 8982 23.76 Mar-00 6447 2007 22692 21914 44606 11192 20.06 Apr-00 6412 2100 31195 7214 38409 13438 25.92 May-00 6995 1556 28175 14961 43136 8967 17.21 Jun-00 7043 1722 24413 16369 40782 8690 17.57 Jul-00 6674 1920 23505 31739 55244 10235 15.63 Aug-00 9623 1996 20925 1197 22122 6577 22.92 Sep-00 3835 1166 11012 1501 12513 4563 26.72 Total 726097 260159 2863329 820586 3683915 1268100 25.61 Number of Full Frame Images Received: 726097 Number of Observing Region Images Received: 3683915 Total: 4410012 Approximate Number of Shutter Moves/CCD Readouts: 7495037 NOTES: * The loss of images is mainly due to BDR overwrites, but there are also occasional DSN dumps which are lost. * It is common to have observing regions which contain more than 64 lines, which requires multiple exposures to make a single observing region image. This is why the number of shutter moves is larger than the number of images received plus those lost. Page 6 ENGINEERING SUMMARY TABLE Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) 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 60.27 1115.9 233820 50214 23.4 N/A Feb-00 60.93 1140.6 235079 56836 23.8 N/A Mar-00 60.72 1132.8 234174 54661 22.9 N/A Apr-00 61.10 1147.0 235252 58348 22.2 N/A May-00 61.00 1143.1 234569 57445 21.2 N/A Jun-00 61.19 1150.3 235622 58946 22.8 N/A Jul-00 61.96 1179.3 238114 66905 19.3 N/A Aug-00 61.27 1153.4 236108 59965 56.9 / 2 21.7 N/A Sep-00 61.48 1161.0 236842 62565 22.1 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 7 PERSONNEL TRAVEL SXT Foreign Travel between 1-SEP-00 and 30-SEP-00 FLETCHER 1-SEP-00 * 3-SEP-00 3 (total of 3 days) HANDY 24-SEP-00 30-SEP-00 * 7 (total of 7 days) HUDSON 1-SEP-00 * 30-SEP-00 * 30 (total of 30 days) NITTA 7-SEP-00 30-SEP-00 * 24 (total of 24 days) TAKEDA 1-SEP-00 30-SEP-00 * 30 (total of 30 days) ---------------------------------------------------------------- Grand Total of 94 days for 5 people NOTE: The "*" signifies travel that actually ends after 30-SEP-00 SXT Foreign Travel between 1-OCT-00 and 31-OCT-00 HANDY 1-OCT-00 * 01-OCT-00 1 07-OCT-00 14-OCT-00 8 (total of 9 days) HUDSON 1-OCT-00 * 1-OCT-00 1 4-OCT-00 13-OCT-00 10 (total of 11 days) MCKENZIE 13-OCT-00 31-OCT-00 * 19 (total of 19 days) NITTA 1-OCT-00 * 1-OCT-00 1 (total of 1 days) TAKEDA 1-OCT-00 * 4-OCT-00 4 7-OCT-00 31-OCT-00 * 25 (total of 29 days) ---------------------------------------------------------------- Grand Total of 69 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-OCT-00 Respectfully submitted, Thomas R. Metcalf Frank Friedlaender Page 8 ================================================================= Montana State Univ Activity Report for August - September 2000 ================================================================= (P. Martens) INTRODUCTION The MSU group carried out SXT operations, data analysis, graduate and undergraduate research, participated in meetings, and performed outreach activities. Alex Pevtsov left the MSU group at the end of July to start a new position at the NSO/SP. We are missing Alex and wish him all the best in his new position. We all greatly enjoyed a visit by Keith Strong to talk about building stronger relationships between MSU and Lockheed Martin for undergraduate internships, etc. There appears to be considerable interest in this possibility on the part of several MSU departments. PROPOSALS All MSU SXT personnel has been active in writing and submitting proposals in the month of August. There are at least five, including a rocket proposal spearheaded by Charles Kankelborg YOHKOH AND SXT OPERATIONS Canfield served as Yohkoh Duty Scientist at Mees Solar Observatory the week of September 12-18. Handy traveled to ISAS on 14-Sep for Yohkoh Ops. He'll be there until 14-Oct. He has updated the ISAS movie platter and subsequently the MSU movie platter. He also started working on an HXT movie archive at MSU, to make these data easily accessible via the web. McKenzie finalized the online SXT Observing Log, and an advertisement has been submitted to SolarNews and to the MaxMillennium mailing list. The website for this query form is: http://solar.physics.montana.edu/sxt_obsrpt/ He will spend October and much of November in Japan, including four weeks of SXT operations. RESEARCH Canfield worked with Jibben on the comparison of SXT jet / MCCD surge events to maps of twist in photospheric magnetic fields inferred from Page 9 Mees vector magnetograms. He worked with Bambeck and Longcope on software for objective recognition of sigmoids in SXT sfd images. He worked with McMullen to determine tilt per unit length of specific NOAA ARs from Mt Wilson data furnished by Bob Howard. He worked with Hudson on the default SXT observing program in support of HESSI. Acton worked on some details of SSC generation and verification. He visited LMATC on 11/12 Sept and discussed the new SSC movie with Freeland, Metcalf and Lemen. Still plenty to do on this eternal project. Kankelborg spent a week at LMSAL learning about pixons and prototyping an image reconstruction code with Tom Metcalf. He also worked on force free field modeling with the "field line" or "fluxoid" model. With Dana Longcope's help, solved some tricky problems-- including a systematic imbalance between magnetic tension and magnetic pressure. Finally he succeeded at reproducing a 2D analytical current sheet solution. Martens worked with Bart de Pontieu on removing the last wrinkles from the paper "Chromospheric Damping of Alfven Waves", by de Pontieu, Martens, and Hudson. They demonstrate qualitatively that the damping of the loop oscillations observed in the aftermath of flares really takes place in the chromosphere, not in the corona. Hence the observed low Q-factor of these oscillations has nothing to do with the coronal Reynolds number being 10 orders of magnitude larger than expected from ab initio estimates McKenzie is working with Canfield and Zach Blehm on sigmoids seen in SXT images, towards a database of regions and events. He further compiled current best estimates of temperatures and densities in a supra-arcade fan, for collaborative work with Hudson and R. Dahlburg. He suggested revisions for a JOP 80 paper: "Active Region Transient Brightenings: A Simultaneous View by TRACE, EIT, and SXT", by Berghmans, McKenzie, and Clette, will be submitted to A&A in October, probably. In short, they find (a) more SXT brightenings per minute than Shimizu did, (b) many of them have EUV components, (c) not all of them have EUV components, (d) the spatial extent and duration of SXR and EUV components differ. SERVICE AND OUTREACH Canfield reformatted the SXT Chief Observer's weekly reports at http://solar.physics.montana.edu/nuggets/ and mirror sites at Lockheed, ISAS, and MSSL. Martens continued working with Ryan McWilliams, a summer student, on the MSU Solar Physics Gallery". It's framework is ready, and all it needs is final polishing. On August 2 he presented a seminar for the MSU summer students, "Interesting Magnetic Field Topologies in the Solar Atmosphere". Page 10 In September Martens spent most of his time preparing and teaching a grad course on "MHD and Plasma Physics", with special attention to space data from Yohkoh, TRACE, and SoHO PUBLICATIONS AND SEMINARS Acton worked on two papers: (1) Paper with Aschwanden, "Temperature Tomography of the Soft X-Ray Corona: Measurements of Electron Densities, Temperatures, and Differential Emission Measure Distributions above the Limb" was returned to ApJ after Markus responded to referees comments, (2) Paper with Pevtsov, "Soft X-ray Luminosity and Photospheric Magnetic Field in Quiet Sun" was put through final edits. McKenzie received referee's report for the Proceedings paper of the Magnetic Reconnection - 2000 Meeting in Tokyo. Made his clarifications and resubmitted. Martens continued working on a paper on filament formation and evolution, very near completion now. Handy completed his magnus opus "On the Evolution of the Solar Photospheric and Coronal Magnetic Fields", Handy, B. N. & Schrijver, C. J., Accepted by ApJ. ============================================================= Univ of Hawaii Activity Report for August - September 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 fair. Observations were obtained on 89% of all scheduled days. The Sun was generally quiet. With the help of an undergraduate student, we have begun generating movies from the MCCD imaging spectrograph. At present these are Page 11 retrospective, as we catch up the past year of data, but in the near future will be true quicklook data, available on the date of observation. LaBonte is continuing work on the mapping of electric currents in several active regions, including the flare productive region AR8210 of May-June 1998. Li presented her recent results on the nature of polar streamers at the IAU Symposium 203 in August, and at the UVCS/SOHO 2000 Science Meeting in September. The SXT data is particularly useful for this study, as nearly a complete solar cycle is available, and the high temperature response of SXT make the streamers highly visible. She is now beginning collaborations with the LASCO team to extend the streamer mapping into the heliosphere and address the connectivity of the structures in the low corona with those in the solar wind. LaBonte spent a week at Marshall Space Flight Center in August. Interactions with the Marshall group included issues of using the SXT data to map the polar corona during the upcoming Ulysses perihelion passage, study of the magnetic evolution and coronal activity in AR8210, and vector magnetic field ambiguity resolution and current computation. PRESENTATIONS AT MEETINGS: Solar Polar Streamers Are Not Polar 2000. Li, J., Jewitt, D., LaBonte, B. J., Acton, L. W. IAU Symp 203, Recent Insights into the Physics of the Sun and Heliosphere - Highlights from SOHO and Other Space Missions. PAPERS PUBLISHED: Nature of Solar Polar Rays 2000. Li, J., Jewitt, D., LaBonte, B. J. Astrophys. J., 539, L67. ============================================================ Stanford Univ Activity Report for August - September 2000 ============================================================ (P. Sturrock) Peter Sturrock is continuing his study of metastable magnetic configurations and their relationship to CMEs and flares. It now seems quite possible that flares, like CMEs, involve the explosive change of state of a metastable magnetic configuration, with the difference that, in the case of a flare, the change produces a new current sheet that reconnects rapidly producing the heating and acceleration which are characteristics of flares. Peter is looking for a procedure to test candidate configurations for metastability. A promising approach is to use the nonlinear energy theorem (see Plasma Physics, pp. 264--266. If the magnetic configuration is parameterized, one would be able to Page 12 study the magnetic energy as a function of the amplitude of the distortion of the field. If the function first increases and then decreases, one can infer that the state is metastable. Falconer (Geophys. Res. Letters, submitted) has recently shown that the probability that a flux tube will erupt to produce a CME appears to be related to the total current and length of the flux tube. We find that Falconer's criterion is similar---but not identical---to our metastability criterion. We hope to acquire more data of the type that Falconer has compiled, to see which criterion is the better predictor of CME events. Peter also continues to collaborate 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 (the divergence equation and the force equation). Jim is currently converting his code from C to IDL. This will be convenient for graphics output and for comparison with data. Jim is also preparing a setup code that will make it easier for a user to modify the conditions imposed on the magnetic field. For more information, see the UC Berkeley contribution to this report. Mark Weber has made progress in the numerical search for metstable magnetic configurations. Beginning with a Gold-Hoyle flux tube belted around the solar equator, the field is relaxed to a stable configuration. The method developed is able to handle the complicated situation of two distinct flux regions with a common border, such as a flux tube embedded in a dipolar corona. Mark is now ready to start calculating field energies to test for metastable configurations. PUBLICATIONS Roald, C.B., Sturrock, P.A., Wolfson, R. 2000, Coronal Heating: Energy Release Associated with Chromospheric Magnetic Reconnec- tion, ApJ, 538, 960. Sturrock, P.A., Weber, M., Wheatland, M.S., & Wolfson, R. 2000, Metastable magnetic configurations and their significance for coronal mass ejections. ApJ, in press. Wheatland, M.S., Sturrock, P.A., & Roumeliotis, G. 1999, An op- timization approach to reconstructing force-free fields, ApJ, 540, 1150. Wolfson, R., Roald, C.P., Sturrock, P.A., Lemen, J., & Shirts, P. 2000, Temperature Structure of the Quiet Corona: an SXT-SUMER Discrepancy, ApJ, in press. Page 13 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, 539, 995. =========================================================================== Solar Physics Research Corp. Activity Report for August - September 2000 =========================================================================== (Karen L. Harvey and Hugh S. Hudson) KAREN L. HARVEY: Activities for August and September: (1) Continued analysis of data on project with Terry Forbes to determine as a function of time the magnetic flux bounded by He I 10830 the two flare ribbons and in the transient coronal holes associated with these flares. The software is essentially in place and is now being tested on HAO/CHIP He I 10830 images of a two-ribbon flare that occurred on 12 December 1998. The magnetic flux encompassed by the flare ribbons and within the transient holes is being treated in two different ways since the event is located N30E30 where geometry is affecting the line-of-sight component of the field, i.e. the fields show the canopy effect. In the first case, we are eliminating from the measurements areas where the canopy effect is evident, that is around the stronger field elements. In the second case, we will model the magnetic field from the line-of-sight component using Sakuri's force-free field model. We are also comparing the locations of the flare ribbons and transient holes with the SXT images for this event to determine how the arcade and transient coronal holes relate spatially and temporally with X-ray dimming events. As mentioned in previous reports, the objective of this study is to determine the reconnection rate of a flare. Two measurements will be made with time using a singe NSO/KP full-disk magnetogram (this assumes that the photospheric field does not change over the observed life of the flare). (2) Continued with a comparison of the coronal holes identified in NSO/KP He I 10830 rotation maps and with corresponding Yohkoh/SXT rotation maps to determine if the structures identified as coronal holes in He I 10830 all are associated with low emission areas and the relation between the mean He I 10830 equivalent width and X-ray emission summed within the hole boundary. We are also investigating what new connections take place as the magnetic fields of emerging and dispersing active regions evolve leading eventually to the formation of isolated, non-polar holes. (3) Preparation of NSO/KP full-disk magnetograms and He I 10830 spectro- heliograms for SXT investigators for studies of the magnetic field and Page 14 He I 10830 structures associated with X-ray structures. Plans for October and November: Continued analysis and study 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 during 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. PUBLICATIONS Papers Published: Harvey, K. L., and Hudson, H. S., "Solar Activity and the Formation of Coronal Holes": Adv. Space Res. 25(9), 1,735 (2000). HUGH S. HUDSON Activities for August and September: The July 14, 2000 flare continues to thrill. We've now done three science nuggets, the most recent being to show off Masuda's successful hard X-ray imaging of the flare ribbons - a first for this instrument and very promising for HESSI. Another angle on this was the occurrence of a seemingly homologous arcade event at the Carrington coordinates of the July 14 flare, but almost two rotations later. The sunspots had virtually disappeared and the field dispersed, but nevertheless the dimensions and orientation of the arcade were astonishingly similar. This event also produced a geoeffective CME. Surely the relationship between the global coronal field and the photospheric field is full of mystery. Wave paper still not finished, drat it, but I helped Nitta with his interesting paper on SXT temperature maps by studying jitter and scatter. The jitter study was brought to a certain point of completeness, and we now think that systematic filter/filter biases of the order of 0.2 arc sec do occur. We don't know why yet. Worked with new SXT chief observer Aki Takeda in getting oriented. Served as SSOC tohban for one week. Plans for October and November: 1. Continue to work on the waves paper. Complete it! Page 15 2. Contribute the jitter correction software and coordinate its use with PREP somehow. Try to figure out the source of the jitter bias. 3. Work with Brigitte Schmieder during her visit to ISAS in October, objective being to extract what we can from the SXT support observations of Flare Genesis. 4. Attend a small workshop at ISSI on solar flares, convened by Peter Cargill. PUBLICATIONS Papers Submitted: Watanabe, T., Sterling, A. C., Hudson, H. S., and Harra, L. K., "Energetics of an Active Region Observed from Helium-Like Sulphur Ions": ApJ (September 2000). Papers Accepted: McKenzie, D. D., and Hudson, H. S., "Downflows and structures above LDE Arcades: Possible Signatures of reconnection?": EPS, September 2000. Hudson, H. S., and McKenzie, D. E., "Hard X-rays from Slow Flares": EPS, September 2000. Papers Published: Sterling, A. C., Hudson, H. S., Thompson, B. J., and Zarro, D. M., "Yohkoh SXT and SOHO EIT Observations of Sigmoid-to-Arcade Evolution of Structures Associated with Halo Coronal Mass Ejections": ApJ 532, 628 (2000). Hudson, H. S., and Kosugi, T., "Acton Receives the AAS Hale Prize," (in Japanese) ISAS NEWS #233 (August, 2000). Harvey, K. L., and Hudson, H. S., "Solar Activity and the Formation of Coronal holes," Adv. Space Res. 25(9), 1,735 (2000). Gopalswamy, N., Hanaoka, Y., and Hudson, H. S., "Structure and Dynamics of the Corona Surrounding an Eruptive Prominence": Adv. Space Res. 25(9), 1,851 (2000). Hudson, H., and Schwenn, R., "Hot Cores in Coronal Filament Cavities": Adv. Space Res. 25(9), 1,859 (2000). TAKEDA AKI: Activities for September: I started working for SPRC in September. The majority of my time was Page 16 spent familiarizing myself with SXT operations. With Hugh Hudson's assistance, I learned to prepare SXT tables, how to transfer them to KSC, and confirm that they are successfully uploaded. I also learned some techniques to check the spacecraft health, the status of incoming data and to handle the formatted data through UNIX commands and IDL programs. I examined dark and terminator images to check the increase of straylight in the SXT instrument, and found no serious increase in those images. L. Acton later recalled that this is a seasonal effect. (http://isass1.solar.isas.ac.jp/~hudson/stray/stray.html, for ref.) Plans for October and November: To complete tasks as one of chief observers, I need to improve my English skills. As a next step, I will have a try at some scientific writings, for example, the 'Science Nugget' web page. Page 17 ------------------------------------------------------------------------------- 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 October 2000 September 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 - 00119 -----------------------------------------------|------------------------------- 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 September 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 | 17 | ------------------------|------------------------|-----------------|-----------