fl047.doschek04 Posted: 07-Apr-92 Updated: 13-Sep-92, 31-Jul-93, 8-Mar-94 Events specified: flare on 5-Jan-92 at 13:15 UT
Collaborators: G.A. Doschek, R.C. Canfield, U. Feldman, J.T. Mariska, K. Strong, AND ANY OTHER WORKERS WHO WOULD LIKE TO PARTICIPATE. In my recent examination of SXT flares in Japan, I noticed that the 5 January 1992 event (M1.9, S11, E10) seems to show a loop filling up with plasma as expected in the chromospheric evaporation picture. A preliminary comparison with magnetograms from both MSFC and Mees Observatory supports the idea that the structure is indeed a loop with the required orientation for the evaporation picture. I have made SXT light curves and contour maps of various portions of the loop (Be and Al filters) and compared them to light curves from BCS, and a preliminary comparison supports the conclusion that the BCS emission comes from the SXT loop. Other brightenings occur at other locations in the SXT images, but these are apparently not the source of the BCS emission. I propose to reduce all the available observations for this flare and publish a paper on the results, for comparison to numerical simulation work to be carried out by Mariska et al. (separate bulletin board topic). HXT observations may be available, and the BCS spectra must be deconvolved into stationary and moving components. Absolute fluxes from SXT and BCS must also be obtained and compared for deriving emission measures.
Update 8-Mar-94
My work on the 5 January flare was completed and is published in ApJ, Doschek et al., 416, 845 (1993). So I guess you can close this topic. Work on this flare is proceeding under another topic headed I think by Wuelser. I may participate in this work.
Update 31-Jul-93
Progress: A paper entitled, "The 5 January 1992 Flare at 13.3 UT: Observations from Yohkoh", has been accepted for publication in the Astrophysical Journal. The authors are: G.A. Doschek, K.T. Strong, R.D. Bentley, C.M. Brown, J.L. Culhane, U. Feldman, A. Fludra, E. Hiei, J. Lang, J.T. Mariska, K.J.H. Phillips, C.D. Pike, A.C. Sterling, T. Watanabe, L.W. Acton, M.E. Bruner, T. Hirayama, S. Tsuneta, E. Rolli, T. Kosugi, M. Yoshimori, H.S. Hudson, T.R. Metcalf, J.-P. Wuelser, Y. Uchida, and Y. Ogawara
ABSTRACT We discuss X-ray spectra and soft X-ray images of an M1.9 flare that occurred on 5 January 1992 near 13.5 UT. These data were obtained with instrumentation on the Japanese Yohkoh spacecraft. They cover the entire rise phase of the flare. To supplement these data we have ground-based magnetograms and H-alpha spectroheliograms. We calculate the electron temperature and emission measure of the flare as a function of time during the early rise phase using X-ray spectral line intensities and line ratios. Using spectral line widths, line profile asymmetries, and wavelength shifts due to the Doppler effect, we calculate the dynamical properties of the flare. The time development of the morphology of the flare, as revealed by the soft X-ray images and the H-alpha spectroheliograms, and the physical quantities inferred from the X-ray spectra, are compared with chromospheric evaporation models. There is an enhancement of blueshifted emission that is closely correlated with the hard X-ray bursts. Heating of one loop in the flare is consistent with a conduction-evaporation model, but heating is found in several structures that do not appear to be physically associated with each other. No standard evaporation model can adequately explain all of the observations.
Update 13-Sep-92
Progress: The available BCS, SXT, HXT, and WBS observations of the 5 January flare (including a Mees Observatory vector magnetogram) have been reduced and a draft manuscript is being circulated among key collaborators. The draft will be more widely circulated to all authors in the near future.