REPORT FROM HAWAII 9 Nov 1992 L. Acton I've now been at the Institute for Astronomy, Univ. of Hawaii, for 2 weeks. It has been a busy and productive time. The first week was spent dealing with the new scattered light problem in the SXT aspect images and preparing for the flare workshop. Last week we had the informal workshop on the 15 Nov 1991 and 24 Nov 1991 flares plus a visit to Mees Solar Observatory on Haleakala, Maui. SCATTERED LIGHT INCREASE IN SXT ASPECT IMAGES On 27 October 1992 between 0430 and 0630 UT a diffuse halo of scattered light appeared in the aspect images and the central brightness of the narrow band image increased by about 6%. The halo only extended to roughly 3 arcmin beyond the normal image and only in the north-south (up-down on the CCD) direction. The leading theory is that this additional light is coming through a hole which has opened up in one of the x-ray mirror entrance filters. This theory will be tested by taking optical exposures with the aspect telescope aperture door closed. At the present level this change has not resulted in any significant impact to the scientific capability of SXT. If the condition substantially worsens it is probable that the thermal load on the x-ray analysis filters may eventually cause light leaks and degradation of the thin filter x-ray images. Note that the shutter is on the CCD side of the filter wheel. The x-ray filters could be protected from constant long exposure to solar heat load by using the diffuser as a shield. This would require more use of the filter wheels than is necessary at present. FLARE WORKSHOP We chose to study the 15 November and 24 October 1991 flares because they were quite well observed by Yohkoh and Mees. Individuals who had worked on these flares and representing all of the Yohkoh instruments as well as other sources of data and interpretation gathered for 3 days here at the Institute for Astronomy for the purpose of informally comparing notes on our findings. Both of these flares gave evidence of early and gradual heating and motion of the neutral line filament. Both also had a period of erratic hard x-ray production in advance of the impulsive phase, provided a series of impulsive hard x-ray spikes and an extended period of hard x-ray production following the impulsive phase. The November flare produced dramatic ejecta in both H-alpha and soft x-rays while the October flare appeared to be fully contained. Both flares had a 2- footpoint structure at the most intense hard x-ray spikes and a looptop flare structure in hard x-rays at other times. It was evident from the SXT images and the Mees magnetograms that there were sometimes magnetic connections between the acceleration site(s) and remote locations even though most of the released energy found its way into the primary hard x-ray loop. A host of questions were raised that need more work. It is our plan to clear up some of the observational questions and reduce more of the data to quantitative values between now and the time of the international meeting at ISAS in February. At that time we hope to present some of this work to the meeting and to continue the cooperative study of these flares at that time. Although most of our detailed questions remain open the discussion last week demonstrated that with patience and careful work it should be possible to make some very good progress in flare physics over the coming years because of the Yohkoh project and associated cooperative work. VISIT TO MEES SOLAR OBSERVATORY On Friday morning R. Bentley, Y. Ogawara, H. Hudson, T. Metcalf and myself arose at 0430 to fly to Maui for the purpose of visiting Mees and discussing Yohkoh science with the observers there. Also, Metcalf and Hudson had specific work to do at Mees. Observations were in progress when we arrived with the H-alpha video coronagraph, the MCCD (I forget the name, this is the instrument that produces an array of H-alpha line profiles in rapid cadence over an active region) and its H-alpha "frame grabber" video, the Stokes polarimeter, the Imaging Vector Magnetograph in the H-alpha polarization mode, and Barry LaBonte's K-line oscillation instrument. It is quite impressive to observe the commitment and technical competence that goes into acquiring the basic data needed to do the science. Flare observing is a tough and often tiresome business. We discovered a rich store of provocative date in the H-alpha coronagraph movies. Over the period since Yohkoh launch there has been some truly spectacular filament eruptions. Several of us are keen to compare these beautiful movies with the SXT movie. Over this coming week I will be working with Len Culhane and Dick Canfield to write up the conclusions and actions items of the workshop as a first step towards developing a description of these flares that can be be used as a basis for future interpretive and theoretical work. It is our plan to do similar work on other flares so that one of the legacies of Yohkoh will be an accurate and quantitative morphological description of a number of flares.