Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for November 1999) 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 Despite everyone's best intentions and hard work, it does not appear that the RFP for contract extension will be released in the current millennium! SOLAR ACTIVITY Solar activity started low in November, but picked up with a flourish, in the form of a huge arcade event at the limb from a new active region in the north, 8759. Solar activity remained moderately high through mid-month, with the GOES background staying above C level. A number of M flares occurred, but still no new X flares. After mid-month, solar activity again decreased. All in all, there were no less than 26 M-class flares, but no X-class events. Often during this period there were as many as a dozen numbered active regions on the disk. AR 8765 (S13, CMP @ Nov. 16) reached 1280 millionths - a big spot group. On the X-ray side, the images again showed us remarkable variations in the trans-equatorial loop structures. Yohkoh's second Mercury transit was a dud scientifically, because it coincided with one of the regular outages of Yohkoh Canopus lock, so that the roll angle could not be re-calibrated. Nevertheless we made images in FFIs and the planet can clearly be seen swimming through the corona. The equivalent TRACE movie - their first - is spectacular and appeared immediately on APOD (http:////antwrp.gsfc.nasa.gov/apod). If we can make it until 2004, we will get a larger planet to work with (Venus). Page 2 At the end of November, solar activity again reached high levels with nine M-class flares and one X-class (!) flare. CAMPAIGNS Yohkoh observed the transit of Mercury on Nov 15. There were no other formal campaigns. SCIENCE Kent Tobiska is developing the SOLAR2000 irradiance model for aeronomy. Up to now Kent's models haven't extended into the x-ray region with very good fidelity. To help him with this task Acton updated SXL2IRRADIANCE.pro and computed the x-ray irradiance in 1 nm bands for the entire Yohkoh mission as daily averages. When the new and improved SXH files are available from the "new movie" work these irradiances will be updated and put online at the NOAA data center in Boulder. Canfield and Van Lew continued their study of observations of SXT jet / MCCD surge events using the Blehm/Pevtsov list of jets and surges inferred from SXT sfd files throughout the mission to date. Interestingly, surges in AR 7260 seems to show predominantly, but not entirely, one handedness. Several other regions were studied, but none were particularly productive of surges. The region currently being studied is AR 7070, which had several SXT jets. Canfield and Colman have started producing preflare velocity movies from Wuelser's list of greatest Mees/SXT hits to look for tether-cutting events similar to those observed by Canfield et al before the Nov 15 event. Several other regions have been studied, and about half of them show moving blueshift episodes during the hours before eruptions. Nitta looked at 36 flares that are known to be generally hot in terms of spatially unresolved soft X-ray measurements to study the super-hot component. For each flare, HXT and SXT images are coaligned that were taken during the impulsive phase, and two times in the decay phase. The findings are summarized as: 1. Only five flares show that the superhot plasma is cospatial (within the uncertainty of coalignment) with the most intense part (i.e., loop top) of soft X-ray emission. 2. Other events show that the superhot plasma is displaced from the soft X-ray loop top source. In nine of them, the hard X-ray source seems to be higher in altitude (not dependent on the loop geometry). 3. Six events show that the superhot plasma is located in a separate structure from the main flare loop. 4. Other flares are more or less complicated. Hard X-ray images could not be synthesized in some of them, presumably because the source was too big. But it seems that the soft X-ray source generally moves in Page 3 the direction of the displacement of the hard X-ray source. 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 November were 108636 accesses and 5734 Mbytes transferred. YOHKOH OPERATIONS AND HEALTH Yohkoh and the SXT continue to function very well. Yohkoh had no difficulties with the Leonid meteor shower. For the Leonids, the Yohkoh team decided to shut down high voltages (reduce them in the case of BCS) as was done last year. This status ran from approximately 00:00 UT Nov. 17 until mid-day Nov. 18. No trouble resulted either from the meteors or from the power commanding. However we did miss an M7.9 event because flare mode cannot be triggered with the high voltages out. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT Bit Map Error 05-Nov-99 Pass 2: 991104-1443 Recovered in the same pass WM SET Error 12-Nov-99 Pass 2: 991112-1136 Recovered in pass 5 Page 4 DATA FLOW Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Sep-97 492855 194344 1999001 408131 2407132 925902 27.55 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 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 2590 1080 8148 8576 16724 4636 21.70 Total 654659 238768 2625156 699084 3324240 1168497 26.01 Number of Full Frame Images Received: 654659 Number of Observing Region Images Received: 3324240 Total: 3978899 Approximate Number of Shutter Moves/CCD Readouts: 6799588 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 (%) 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 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 59.92 1102.6 231061 47177 23.2 N/A Dec-99 N/A N/A N/A N/A 0.0 N/A Jan-00 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-NOV-99 and 30-NOV-99 CANFIELD 1-NOV-99 * 12-NOV-99 12 (total of 12 days) FLETCHER 1-NOV-99 * 5-NOV-99 5 (total of 5 days) HUDSON 1-NOV-99 * 14-NOV-99 14 1-NOV-99 * 21-NOV-99 21 27-NOV-99 30-NOV-99 * 4 (total of 39 days) MCKENZIE 1-NOV-99 * 25-NOV-99 25 (total of 25 days) NITTA 10-NOV-99 26-NOV-99 17 (total of 17 days) SLATER 30-NOV-99 30-NOV-99 * 1 (total of 1 days) ---------------------------------------------------------------- Grand Total of 99 days for 6 people NOTE: The "*" signifies travel that actually ends after 30-NOV-99 SXT Foreign Travel between 1-DEC-99 and 31-DEC-99 HUDSON 1-DEC-99 * 12-DEC-99 12 28-DEC-99 31-DEC-99 * 4 (total of 16 days) NITTA 16-DEC-99 28-DEC-99 13 (total of 13 days) SLATER 1-DEC-99 * 21-DEC-99 21 (total of 21 days) ---------------------------------------------------------------- Grand Total of 50 days for 3 people NOTE: The "*" signifies travel that actually ends after 31-DEC-99 Respectfully submitted, Thomas R. Metcalf Frank Friedlaender Page 7 7 ======================================================================= Montana State University Activity Report for October 1999-November 1999 ======================================================================= (R. Canfield) =======INTRODUCTION The MSU group carried out SXT operations, data analysis, graduate and undergraduate research, participated in meetings, and performed outreach activities. The highlight of this period was Mark Weber's successful thesis defense on November 8th. His dissertation, "Rotation Patterns in the Large-Scale Solar Corona", consists of three papers based on SXT data. YOHKOH AND SXT OPERATIONS Handy served as SXT Chief Observer during the first week of October. McKenzie served as SXT Chief Observer during October and November, coordinating campaign observations with SoHO and TRACE (flare and arch filament campaigns). Yohkoh weathered the Leonids and a transit of Mercury, and we were visited by the Crown Prince and Princess of Japan. McKenzie experimented with alternative AEC parameter values, to help us get "controlled" over-exposures during flare mode, instead of the fixed exposures heretofore used for half- and quarter-res images. Canfield served as Yohkoh duty scientist at Mees from October 26 to November 2, and as Yohkoh SSOC tohban from November 1 - 7. MEETINGS Acton gave two invited talks at the African Summit on Science and New Technologies at Libreville, Gabon. He also worked on the new SXT movie in preparation for for the Yohkoh 8th anniversary science conference on Explosive Phenomena in Solar and Space Plasmas. Martens gave a seminar at the University of Calgary in Alberta (a center for auroral research) on "Flares and Eruptions on the Sun -- The Drivers for Space Weather". He gave a seminar for the MSU Electrical and Mechanical Engineering departments on "Space Science & Engineering at MSU -- Plans and Opportunities". Finally, he led the seminar "Solar & Stellar Winds" at MSU. RESEARCH Several undergraduates are working with SXT data. Junior Zachary Blehm is identifying all X-ray jet/cusp events throughout the mission, for a larger-scale study akin to the sigmoids study featured in the March SSU. Sophomore Trish Van Lew is studying twisting episodes (helicity Page 8 transfer) in H-alpha surge events associated with them. Finally, Junior Angela Colman is producing preflare velocity movies from the best-observed Mees/SXT flares, looking for tether-cutting events similar to those observed by Canfield et al before the Nov 15 event. >From SXT, HXT, TRACE, and GBO data is is clear that we have sufficient data on flare events observed during the Whole Sun Month and Max Millennium sigmoids campaign to test topological models of sigmoids. Canfield, Hudson and Pevtsov worked on a review article on sigmoids as precursors of solar eruptions, including sections on SXT observations, magnetic helicity, and theory. Kent Tobiska is developing the SOLAR2000 irradiance model for aeronomy. Up to now his models haven't extended into the x-ray region with very good fidelity. To help him with this task Acton updated SXL2IRRADIANCE.pro and computed the x-ray irradiance in 1 nm bands for the entire Yohkoh mission as daily averages. These results were also sent to Lean and Mariska at NRL. When the new and improved SXH files are available from the new SXT movie work these irradiances will be updated and put online at the NOAA data center in Boulder. Martens and McKenzie critically examined the conflicting existing publications on X-ray emission from coronal holes, as McKenzie returned to the SXT scattering problem, improving his understanding of Foley's method and refining his iterative deconvolution scheme. Martens and Kankelborg collaborated on the topological implications of constant cross-sections of coronal loops. McKenzie worked on his "supra-arcade down-flows" paper, which compares the flow field observed by SXT above LDE arcades with the available contemporary EUV and H-alpha data. SXT sees down-flows that are evidenced both by X-ray dark features and by bright, emitting, shrinking loops. EUV & H-alpha see the arcade and post-flare loops, and coronal rain in the loops, but see nothing above the arcade in the region where the SXR motion is seen. Weber and Martens are writing a letter for ApJ: "Axial Fields in Quiescent Prominences", studying the effects of decaying active regions on polarity inversion lines. The mechanism may provide a simple explanation for the origin of the observed axial field directions in filaments. Weber and Longcope worked on SXT observations showing that the south polar coronal hole extension alternated abruptly between two rotation modes. Using the flux-transport model of Sheeley, Nash, & Wang, they developed an analytic approximation for the surface flux distribution and show how one of the modes is a consequence of the presence of an "activity nest". SERVICE AND OUTREACH Martens refereed four papers, and worked on the proceedings for IAU 195, Page 9 held earlier in the year at MSU. Acton chaired a NASA peer-review in Washington, DC. Canfield transformed SXT Weekly Notes to Nuggets on http://solar.physics.montana.edu/nuggets. Davey was involved primarily in updating software on various systems and various programming projects. He upgraded to IDL 5.2 on all machines and discovered the DEC Unix unresolved symbol problem on the license manager. He upgraded the wu-ftpd server to 2.6 following last weeks security advisories and added SSH access to our primary server mithra. The solar group acquired its own LAN switch to which all machines are now connected. Together with improved inter-building networking, our access to the world beyond the last best place is significantly improved. PUBLICATIONS: Papers Published: ---------------- "Coronal Heating by Resonant Absorption: the Effects of Chromospheric Coupling", A.J.C. Belien, P.C.H. Martens, and R. Keppens 1999, Astrophys. J., 525, 478-493. "Nonlinear Dynamics and Wave Heating in Solar Coronal Loops", A.J.C. Belien, P.C.H. Martens, R. Keppens, and G. Toth 1999, in 3rd Advances in Solar Physics Euroconference on: "Solar Magnetic Fields and Oscillations", ASP Conference Series, 184, 248-252, eds. B. Schmieder, A. Hofmann, and J. Staude. Papers Accepted: ---------------- "Recombination Coefficients for C II Lines" 2000, Astronomy and Astrophysics, in press. "Time Variability of the "Quiet" Sun Observed with TRACE. II. Physical Parameters, Temperature Evolution, and Energetics of EUV Nanoflares", M.J. Aschwanden, T.D. Tarbell, R.W. Nightingale, C.J. Schrijver, A. Title, C.C. Kankelborg, P.C.H. Martens, H.P. Warren, and S. Krucker 1999, ApJ. "Rotation Patterns in the Large-Scale Solar Corona", M. Weber, PhD. thesis, MSU College of Graduate Studies, November 1999. Papers Submitted: ----------------- "The Dynamical Influence of the Transition Region and Chromosphere on the Heating of Coronal Loops by Resonant Absorption of Alfven Waves", by A.J.C. Belien, P.C.H. Martens, and R. Keppens, SOHO 8 Proceedings, 1999. Page 10 ============================================================= Univ of Hawaii Activity Report for October 1999-November 1999 ============================================================= (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 during this interval, with observations obtained on 75% of all possible days. New tools for operations planning and data summary include quicklook movies of the active regions observed by the Imaging Vector Magnetograph and graphical display of the daily observing log, both linked at http://www.solar.ifa.hawaii.edu/Daily/mees_obs.html LaBonte has completed reduction of the IVM magnetogram movie sequences of active regions observed in 1998. These are now being used to deduce magnetic evolution and electric currents for a variety of studies. He will present some results at the AGU meeting in December. Li finished her manuscript on the global corona during the solar minimum, and has submitted it for publication. By mapping the coronal emission at a given altitude as a function of position angle and time, she found that the streamers over the polar coronal holes were easily separated between those on the Earthward hemisphere, which rotate prograde, and those on the invisible hemisphere, which rotate retrograde. She has carried her work forward to the rise phase of the cycle and finds that multiple streamers are detected simultaneously. The streamers visible over the pole are related to low latitude active regions but clearly are rooted at higher latitudes, indicating a largescale organization of the corona. She is preparing this work for publication. Li has also begun the analysis of the 1999 June Yohkoh/SOHO/TRACE campaign streamer observations. Page 11 ============================================================ Stanford Univ Activity Report for October 1999-November 1999 ============================================================ (P. A. Sturrock) Colin Roald and Peter Sturrock have continued their investigation of the coronal heating theory mentioned in previous reports, in which the key process is magnetic reconnection at the chromospheric level. Our model involves the emergence of magnetic bipoles within supergranulation cells, the migration of magnetic elements into the network, and "collisions" of elements of opposite polarity (leading to "cancellation") in the network. The paper by Sturrock, Roald and Wolfson (mentioned in the last two-month report) has now been published in Ap J Letters, and another by Roald, Sturrock and Wolfson has been accepted for publication in Ap J. Sturrock continues to collaborate with Mike Wheatland concerning the optimization-function approach to constructing force-free magnetic fields. This method has been applied to a known 3D force-free-field model due to Low and Lou, for which all the boundary conditions are known, with very satisfactory results. An article by Wheatland, Sturrock and Roumeliotis has now been submitted to the Astrophysical Journal. The next step is to modify the procedure so that it can be applied to realistic solar cases for which the vector field at the photosphere is known, but the conditions above the photosphere are unknown. Jim McTiernan is now collaborating with Sturrock and Wheatland on this problem, and we are pursuing what now appears to be a promising approach. 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. We can generalize this procedure by multiplying each such term by a weighting function. If the weighting function drops to zero at the outer surface of the domain, then the boundary condition at that surface becomes irrelevant. As another extension of the original Roumeliotis procedure, we plan to 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. It appears that this optimization-function procedure should be applicable to a wide range of problems. For instance, if it turns out that r-mode oscillations play a role in modulating solar activity, the optimization-function approach may be a useful way to simplify what can be a rather gruesome calculation. Peter is also collaborating with Mike Wheatland 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 Page 12 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 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. We are developing a procedure to calculate the equilibrium state of such a topology. It will be interesting to see whether or not such configurations can have a total energy in excess of the energy of the corresponding open configuration. Jim Klimchuk and Peter have been discussing the possible role of wave pressure as an explanation of loop-top condensations, as seen by SXT, and maybe in loop-top emission from flares as seen by HXT. This possibility has been proposed by Litwin and Rosner (Ap J (Letters) 506, L143). The formula for wave pressure derived by Litwin and Rosner is unusual, but we find that it is equivalent to the more familiar expression if there is no resistive dissipation. We find that, for a field strength of 100 Gauss and a plasma electron density of 10^9 cm^-3, plasma can be confined at the top of a loop of height 30,000 km if the oscillation at the top of the loop has a velocity amplitude of order 150 km s^-1, or a displacement amplitude of order 500 km. The requirements are larger for a higher loop. We are looking into possible explanations of such oscillations, and the probable lifetime of the oscillations, once excited. I regret to say to Colin has decided to leave solar physics to join a start-up company in Silicon Valley. I have asked him to help fund solar research as soon as he has made his first billion. If all goes well, I will be searching for a replacement in the New Year. Publications 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. Sturrock, P.A., Roald, C.B., & Wolfson, R. 1999, Chromospheric magnetic reconnection and its implications for coronal heating, Ap. J. (Letters), 524, L76. Wheatland, M.S., Sturrock, P.A., & Roumeliotis, G. 1999, An Optimization Approach to Reconstructing Force-Free Fields, ApJ, submitted Wolfson, Roald, Sturrock and Weber, 1999, "Coronal X-ray Brightness and Photospheric Magnetic Field: A Study in Correlations," ApJ, in press Page 13 Wolfson, Roald, Sturrock, Lemen and Shirts, 1999, "Temperature structure of the quiet corona: an SXT-SUMER discrepancy", ApJ, in press =========================================================================== Solar Physics Research Corp. Activity Report for October 1999-November 1999 =========================================================================== (K. Harvey and H. Hudson) KAREN L. HARVEY: Activities for October and November: (1) Continuing 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 deduce the height structure of the associated coronal/chromospheric bright points. The NSO/KP magnetic flux measurements provide a precise co-alignment of magnetic, velocity and intensity structures at two levels of the atmosphere separated by about 1000 km. These data were compared with chromospheric and coronal Intensity images to establish the timing of the cancellation of the opposite polarity structures in the chromosphere and photosphere. We found that most, if not all, of the cancellation sites are consistent with a picture that magnetic flux is retracting below the surface following the reconnection of the previously unrelated opposite polarity network elements. (2) Began a comparison of coronal holes observed by the SXT with 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. (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 December 1999 and January 2000: Continued analysis of (1) the association of coronal holes observed in He I 10830 spectroheliograms and the SXT full-frame images; (2) the XBP data collected during several observing campaigns, concentrating on the Page 14 more recent runs, to derive the height and temporal structure of coronal and chromospheric bright points associated with magnetic flux cancellation and emergence; (3) 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. PUBLICATIONS: Papers Accepted "Does Magnetic Flux Submerge at Flux Cancellation Sites?", Harvey, K. L., Jones, H. P., Schrijver, C. J., and Penn, M. J., Solar Physics, accepted (1999). HUGH S. HUDSON Activities for October and November: I attended the HESSI workshop and presented papers on the May 6 wave, recruiting Marian Karlicky as co-author of the proceedings paper - he has good dynamic spectra and interesting ideas. The other presentation at this nice meeting was on "slow LDEs," co-authored with Dave McKenzie. Shrugging all shyness aside, I submitted an ApJ Letter version of the implosion conjecture dreamt up for the Monterey workshop in September. This writeup was a hasty and very short writeup, and the referee rejected it - not disliking the idea, but disliking the terseness of the text. Accordingly I increased the length but did not go so far as to add cartoons, which some fans of the idea had proposed. Working with HESSI, or rather watching people work with it, suggested to me that a soft X-ray reflection filter might be easy to do with the slat-stacking technology developed for thick HESSI grids by Frank van Beek (Technical University of Delft). A reflection filter would basically be a low-pass filter, which would provide great flexibility in conjunction with normal thin-film transmission filters. I am just sorry that this idea did not appear prior to Yohkoh, but in the meanwhile I'm working out some of the rather simple details. Interested persons, please see http://isass1.solar.isas.ac.jp/~hudson/reflection/filter.html. Planned activities for December 1999 and January 2000: 1. Attend the AGU Winter meeting, to present the big flare paper (co-authors Alexander and Parnell). 2. Finish the May 6 wave paper, hoping to get it out the door before the anniversary of its SXT science nugget (December 25). 3. Finish contributions papers for the HESSI workshop. Page 15 4. Attend the January workshop on the Whole Sun Month, emphasis on the sigmoid observations. 5. Finish helping Dick Canfield with his IEEE tutorial paper on solar sigmoids. Distribute this paper to doubters. PUBLICATIONS: Papers Published "TRACE and Yohkoh Observations of High-Temperature Plasma in a Two-Ribbon Limb Flare": Warren, H. P., Bookbinder, J. A., Forbes, T. G., Golub, L., Hudson, H. S., Reeves, K., and Warshall, A., ApJ 527, L121 (1999). Papers Accepted "Coronal Mass Ejections at High Temperatures," Hudson, H. S., (Proc. Nobeyama Conference, Kiyosato, Japan). Papers Submitted "Coronal Magnetic Implosions": H. S. Hudson, ApJ Letters. =========================================================================== University of New Hampshire Activity Report for October 1999-November 1999 =========================================================================== (T. Forbes) IN PRESS: 1. Lin, J., and T. G. Forbes, The effects of reconnection on the CME process, J. Geophys. Res., in press, 1999. SUBMITTED: 2. Forbes, T.G., A tutorial review on CME genesis, J. Geophys. Res., submitted, 1999. Page 16 ======================================================================= University Of California Activity Report for October 1999-November 1999 ======================================================================= (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. McTiernan has re-written the HXT analysis routine hxt-multimg so that it works correctly for HXT data taken in calibration mode. Griffiths, Fisher, Woods, Acton and Siegmund have revised and resubmitted their paper ``Simultaneous SOHO and Yohkoh Observations of a Small Solar Active Region'' to ApJ, in response to the referee report. Fisher and Griffiths have analyzed vector magnetogram data in conjunction with X-ray flare emission from GOES to test whether or not the ``global magnetic variables'' that were well correlated with quiescent heating are also correlated with flare energy release. The results thus far show only very weak correlations of flare energy dissipation with magnetic flux or the area integral of unsigned electric current. 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 December 1999 November 1999 |------------------------------- | 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 November 1999 |------------------------------- |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 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office