SXT Status Report March 6, 2000 to April 2, 2000 (Weeks 11-14) L. Fletcher, H. Hudson, N. Nitta SUMMARY This is a four-week interval because of clerical confusion! SXT has had no problems of any sort. Solar activity was pretty high. Max Millenium campaign #6 deployed us and many other observatories in search of polarization signatures. SOLAR ACTIVITY Solar activity was moderate to high - 30 M flares and two X flares, both of which Yohkoh managed to avoid. Predictions of this activity seemed to have missed in both directions, the subject of the science nugget for March 24. In the selected active region for Max Millennium campaign #6, we noted that the flares initially did not seem eruptive. This changed with time. The AR structure did not show a clearly-defined coronal sigmoid, and instead consisted of multiple loops. OBSERVING CAMPAIGNS The Max Millenium campaign to study polarization signatures in flares (see http://www.lmsal.com/~metcalf/MaxMillennium/maxmil06.html ) proceeded pretty auspiciously, with the probable successful joint observation of many flares in AR 8906. The X flares (March 22-24), unfortunately were in AR 8910. The TRACE data apparently will be the definitive dataset on UV behavior at high resolution and frequent sampling, and in we have had some flares strong enough to give Yohkoh HXT high time resolution too, including examples of the wide-separation hard-spectrum footpoint morphology. Among the ground-based observations, there are some H-alpha observations from Big Bear with ultra-high time resolution. We have instituted a scheme by which the SXT chief observers will keep a watch out for interesting developments of various types. There is a Web page with details at http://isass1.solar.isas.ac.jp/sxt_co/alerts.html for those interested. We're doing this because the SXT chief observers don't rotate so frequently, helping the attention span, and because some things (as listed) are seen first and best on the SXT data. 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 problems, especially no further Y2K bugs. In view of the re-analysis of our telemetry support at the Santiago site, we generated some statistics. Surprisingly, this site provided almost 1/4 of the total NASA support during 1999. For details, see please: http://isass1.solar.isas.ac.jp/~hudson/scratch/santiago.html As of the beginning of April, we seem to have been reduced to one Santiago pass per day. While not ideal, the single pass is by far the most important contribution Santiago can make. SXT OBSERVING SEQUENCE TABLES ------------------------------------------------------------- UT Date & Time Pass Table ID ============================================================= Monday PM 06-Mar-00 14:09 4 000306 P4 ARS1 DARKCAL Tuesday PM 07-Mar-00 09:13 2 000307 P2 ARS1 DIFF Tuesday PM 07-Mar-00 12:38 4 000307 P4 ARS1 STD Wednesday PM 08-Mar-00 12:49 4 000308 P4 ARS1 STD Thursday PM 09-Mar-00 13:00 4 000309 P4 ARS1 STD Friday PM 10-Mar-00 09:45 3 000310 P3 ARS1 STD Saturday PM 11-Mar-00 11:39 4 000311 P4 ARS1 STD Monday PM 13-Mar-00 08:34 3 000313 P3 ARS1 DARKCAL Tuesday PM 14-Mar-00 10:28 4 000314 P4 ARS2 DIFF+MM6 Wednesday PM 15-Mar-00 07:13 3 000315 P3 ARS2 MM6 Thursday PM 16-Mar-00 07:24 3 000316 P3 ARS0 MM6 Thursday PM 16-Mar-00 09:07 4 000316 P4 ARS2 MM6 Friday PM 17-Mar-00 09:17 4 000317 P4 ARS2 MM6 Saturday PM 18-Mar-00 07:45 4 000318 P4 ARS1 STD Monday PM 20-Mar-00 08:06 4 000320 P4 ARS2 DARK+MM6 Tuesday PM 21-Mar-00 06:34 4 000321 P4 ARS2 DIFF+MM6 Wednesday PM 22-Mar-00 03:19 2 000322 P2 ARS2 MM6 Thursday PM 22-Mar-00 06:44 4 000322 P4 ARS2 MM6 Thursday PM 23-Mar-00 05:12 3 000323 P3 ARS2 MM6 Friday AM 24-Mar-00 01:58 2 000324 P2 ARS2 MM6 Saturday AM 25-Mar-00 00:27 1 000325 P1 ARS2 MM6 Saturday PM 25-Mar-00 05:34 4 000325 P4 ARS1 STD Monday 27-Mar-00 00:47 4 000326 P2 ARS2 DIFF+MM6 Tuesday 27-Mar-00 23:16 1 000327 P1 ARS2 MM6 Wednesday 28-Mar-00 02:41 3 000327 P3 ARS2 MM6+DK Thursday 29-Mar-00 01:08 3 000328 P3 ARS1 STD Thursday 30-Mar-00 01:19 3 000329 P3 ARS1 STD Saturday 01-Apr-00 01:40 4 000331 P4 ARS1 VLA ============================================================ SCIENCE General: Nothing much to report, except that the small flares of the campaign have had many interesting features. As noted elsewhere, eruptivity hasn't been one of them, though. Seminars: 16-Mar-00: H. Hudson (SPRC) "Non-coronagraphic observations of CMEs." This was a replay of the pretty pictures shown by the speaker at the ISTP workshop the preceding week. 23-Mar-00: L. Fletcher (LMSAL) "Evidence for spine and fan reconnection in a solar flare." Much better attended than the previous week's seminar. Science Nuggets: 10-Mar-00: "A Knotty Flare" (preparation for Max Millenium #6). The "knots" refer to compact emission features in the TRACE transition-region observations from a flare of June 22, 1999, also well-observed by Yohkoh instruments. This anticipates the kind of data expected from the current Max Millennium campaign, to which have been added the H-alpha imaging spectroscopy that could show up polarization signatures. 17-Mar-00: "Controlled Explosions" comments on the lack of eruptivity in the MM#6 active region. 24-Mar-00: "Amateur Flare Forecaster" describes the predictions misses mentioned above in this report; but it would be hard to call the SXT chief observers "amateurs" by now. 31-Mar-00: "The Inscrutable DEM" shows a pretty picture and then launches into a turgid discussion of DEM in Withbroe solar-wind models. With lots of line plots, this is not the most exciting science nugget, but... we need to be quantitative about things! For real non-experts, DEM stands for "differential emission measure." 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 Much traffic: Lyndsay Fletcher arrived and left, and so did Nariaki Nitta; Phil Shirts returned to Palo Alto. Hudson returned from the "eruptive events" workshop, then made another excursion for the ISTP workshop at GSFC. Loren Acton arrived. TOHBANS (spacecraft operators) Tohbans for week 11 SSOC: N. Shinohara, T. Shimizu KSC: Y. Yamauchi, S. Yashiro SXT_CO: L. Fletcher SXT_SW: P. Shirts Tohbans for week 12 SSOC: Y. Katsukawa, T. Naito KSC: T. Watanabe, K. Kobayashi SXT_CO: L. Fletcher, H. S. Hudson SXT_SW: - Tohbans for week 13 SSOC: S. Masuda, Y. Nishino KSC: K. Kobayashi, K. Yoshimura SXT_CO: L. Fletcher, N. V. Nitta SXT_SW: - Tohbans for week 14 SSOC: K. Akita, K. Hori KSC: K. Yoshimura, S. Kawashima SXT_CO: N. V. Nitta, H. S. Hudson SXT_SW: -