SXT Status Report July 25- August 6, 2000 (Weeks 31-32) H. Hudson SUMMARY High activity collapsed - six M-class flares, but all at the begnning of the interval. SXT and Yohkoh performed properly, with no technical difficulties. SOLAR ACTIVITY The six M-class flares came from regions 9087, 9090, or 9097, which all crossed the W limb during Week 31 (first week of the reporting period). The M8 on July 25, from a medium-sized region then near disk center, inspired a science nugget (see below). These regions were not the "super region" 9077 from July, whose return as 9115 looks not so super. The flare trigger level returned to normal level during this interval. Although an official report isn't available yet, it appears possible that the July 25 X-class flare was responsible for the premature loss of the ASCA satellite, a sister of Yohkoh. The mechanism is a complicated one and we'll try to report it here when the knowledge becomes available. OBSERVING CAMPAIGNS Yohkoh and SXT supported the SERTS observations of DEM, in conjunction also with the VLA, in week 31. The rocket flight was a success. SXT images were unfortunately overexposed in the core of the target region because of the presence of a C-class flare in its decay phase during the rocket flight. Please see our webpages for more details about campaigns past and future: http://isass1.solar.isas.ac.jp/sxt_co/sxt_catalog.html http://isass1.solar.isas.ac.jp/sxt_co/sxt_future.html SXT INSTRUMENT STATUS AND CALIBRATION ACTIVITIES No unusual acivities took place during the reporting interval. We ought to have done a CCD bakeout but activity was too high to risk taking a day off. The bakeout is now planned for Week 33. TELEMETRY DOWNLINKS Week Wallops Goldstone Canberra Madrid NASA ISAS 31 26 5 1 3 35 31 32 27 5 0 7 39 31 The pattern of ISAS telemetry coverage is now changing because of the reduced need for ASCA tracking. It appears that we will be able to get up to several dumps to the new 34-m antenna at KSC each Sunday, which is good; unfortunately we may not be able to use as many as we'd like to because of the limited capacity for on-board commands. We cannot yet do uplinks from the 34-m. ISAS is now reconsidering its strategy for computer security, and there have been discussions led by S. Nagata during the weekly operations meetings. It appears that unencoded password functions such as telnet and ftp may not be allowed in the future. It is not clear yet what impact this will have on SolarSoft and the Yohkoh database system, which rely upon a lot of routine automated file transfer. The partial solar eclipse of July 31 was not observed. SXT OBSERVING SEQUENCE TABLES ------------------------------------------------- JST Day UT Date & Time Pass Table ID ================================================= Tuesday AM 24-JUL-00 19:22 4 000724 P4 ARS1 DIFF* Wednesday AM 25-JUL-00 14:24 2 000725 P2 ARS1 DARK Wednesday AM 25-JUL-00 19:30 5 000725 P5 ARS1 STD* Thursday AM 26-JUL-00 14:31 2 000726 P2 ARS2 VLA Thursday AM 26-JUL-00 16:13 3 000726 P3 ARS2 SERTS* Thursday AM 26-JUL-00 19:38 5 000726 P5 ARS1 STD* Friday AM 27-JUL-00 12:57 2 000727 P2 ARS2 VLA Friday AM 27-JUL-00 18:03 5 000727 P5 ARS1 STD* Saturday AM 28-JUL-00 13:04 2 000728 P2 ARS1 STD Sunday AM 29-JUL-00 14:54 3 000729 P3 ARS1 STD* Tuesday AM 31-JUL-00 15:09 4 000731 P4 ARS1 STD* Tuesday PM 01-AUG-00 10:09 1 000801 P1 ARS1 RAPID Wednesday AM 01-AUG-00 15:07 4 000801 P4 ARS1 DIFF* Wednesday PM 02-AUG-00 11:59 3 000802 P3 ARS1 DARK Thursday PM 03-AUG-00 08:42 1 000803 P1 ARS1 RAPID Friday PM 04-AUG-00 10:32 3 000804 P3 ARS1 RAPID Saturday PM 05-AUG-00 12:22 4 000805 P4 ARS1 STD Lots of tables! ================================================= Data reformatting is complete through 15-Jul-00 (week 00_29). SCIENCE Seminar (August 3) S. Nagata (ISAS): "Multi-temperature structure of the solar corona observed by Yohkoh and SOHO" Nuggets 21-Jul-00: "Cusps upon cusps" Successive major flares in the same active region left different cusp structures - in other words, the second event apparently restructured the field from the configuration just established the day before. The opposite kind of behavior had been reported in a science nugget a couple of months ago, so we continue to be surprised. 28-Jul-00: "Flare, II, halo" Discussion of a SXT observations of a nice impulsive M-class flare associated with a Type II burst, July 25, 2000. Some speculations included about pressure pulses, halo CMEs, etc. 4-Aug-00: "Remarkable particle track" What must be a rare occurrence in a PFI: a long (1.4 mm) curved particle track. This nugget discusses the ins and outs of particle tracks in CCDs, then winds up with the Bastille Day fireworks of the "snowstorm" observed by EIT (thanks to Sam Freeland). The full list of nuggets is kept on http://isass1.solar.isas.ac.jp/sxt_co/index.html and the current week's nugget also normally resides on http://isass1.solar.isas.ac.jp/sxt_co/SXTweekly.html PERSONNEL Lyndsay Fletcher arrived August 5. TOHBANS (spacecraft operators) Tohbans for week 31 SSOC: Y. Suematsu, H. Isobe KSC: S. Masuda, T. Sekii SXT_CO: B. Handy SXT_SW: - Tohbans for week 32 SSOC: N.Shinohara, T.Shimizu KSC: T.Miyawaki, H.Ishizaki SXT_CO: H. Hudson SXT_SW: -