Submitted: 9 June 1999 JOP098 version 2 -- SOHO Joint Observation Programme. submitted by: Neale Ranns (ndrr@mssl.ucl.ac.uk) MSSL Dale E. Gary (dgary@njit.edu) New Jersey Institute of Technology Center for Solar Research Richard Canfield (canfield@mithra.physics.montana.edu) Montana State Participating Instruments and Observatories SoHO-CDS/EIT/MDI, TRACE, YOHKOH, OVRO Solar Array, Big Bear Solar Observatory, Mees Solar Observatory, Siberian Solar Radio Telescope, Kitt Peak, Marshall Space Flight Center, Meudon Observatory, Alfred University H-alpha Video System, RATAN 600 Radiotelescope. TITLE ----- 3-D Structure of Flaring Active Regions OBJECTIVES ---------- This second version of JOP098 represents the first Max Millennium Coordinated Observing Campaign, the purpose of which is meant as a "warm-up exercise" before the launch and subsequent inclusion of HESSI into the campaign. Its objectives are threefold: * To obtain multi-wavelength observations before, during and after solar flares over a wide range of temperatures and heights in the solar atmosphere, for the purpose of building a three-dimensional, topological framework for interpreting HESSI data when they become available, and to bring forth questions that joint studies with HESSI should try to answer; * To work out methods and lines of communication among ground-based and space-based observers that can be utilized during future HESSI observations; * To form collaborative groups to work on joint analysis of data, so that such groups will be in place and familiar with available data from current instruments. SCIENTIFIC GOALS ---------------- The procedure envisioned and the scientific goals of this campaign are: * Obtain vector magnetic field measurements in the photosphere of a flare-producing active region over several days, suitable for extrapolation. This includes electric current measurements to enable non-linear force-free extrapolations. * Obtain flare observations of emission from thermal and high-energy particles in EUV, soft X-rays, hard X-rays, and radio, and combine them spatially within the 3D framework derived from the other observations. * Study the properties of the high-energy particles based on timing, spectral diagnostics, spatial relationships, and spatial evolution in an attempt to define o when and where in the solar corona the energy release takes place, o how and where the particles are trapped or precipitate, and o what are the characteristics of the acceleration process. * Use what we learn from the process to determine which steps are adequately known, which steps contain gaps where more work is needed, and how the expected HESSI data will affect this kind of comparison. Although not a goal of the campaign, observations of ejecta such as CMEs, filaments, and surges are also of interest in placing the flare in context. TARGET ------ The target for this campaign is any flare-producing active region, although the preferred one would be near disk center in the first days of the campaign to establish good photospheric magnetogram measurements. Generally the region should be at least beta-gamma and in a growth phase early in the campaign. The region will be followed over several days, and ideally could be tracked over the west limb. SCHEDULING CONSIDERATIONS ------------------------- The target date for the start of the campaign is 15 June. Once started, the duration of the campaign will be two weeks, during which the same active region will be observed each day. If the region strongly decays or rotates over the west limb, a new active region target may be selected if during the two-week period, or if no other suitable region exists the campaign may be ended early. In any case, the campaign should be completed before the end of July, in order not to conflict with the Whole Sun Month 3. INSTRUMENT OBSERVING SPECIFICATIONS ----------------------------------- SoHO-CDS -------- Continuous tracking of the target active region. Imaging in FeXIX, FeXVI, MgX, OV and He1 at 10 minute cadence. The field of view will be 3 by 3 arc-minutes at a resolution of 4arc-seconds. SoHO-EIT -------- Full Sun synoptic imaging in FeXII, with occasional imaging in FeIX, FeXV and HeII. SoHO-MDI -------- Full disk magnetograms, continuum imaging and Dopplergrams at a maximum possible time resolution allowable, dictated by DSN contact and present MDI observing mode. TRACE ----- Continuous Tracking of the target active region in flare response mode. Continuous imaging in CIV or Lyman Alpha at full resolution (0.5 arcsecs) with a field of view of 6 by 6 arcmins. Images taken in all other filters every 10 minutes for contextual purposes. YOHKOH-SXT ---------- Continuous Tracking of the target active region in normal imaging mode. YOHKOH-HXT ---------- Will operate in it's standard mode of observation, which gives up to 0.5 sec time resolution in four energy channels. OVRO ---- Daily, 43 frequencies, 1-18 GHz, dual polarization, 12 s time resolution, 10 baselines, 15" spatial resolution. If flare-triggering available: auto-switch to 10-12 frequencies, 1-18 GHz, Stokes I, 2 s time resolution, 10 baselines. BIG BEAR SOLAR OBSERVATORY -------------------------- In quiet periods: 10" center bench, video-magnetograph; 26" east bench, H-alpha center line. During flares: 10" east bench, fast (10 ms) He D3 observations of precipitation kernels (2.1 x 2.1 arcmin field of view); 26" benches, H-alpha center line, +0.6 A, and -0.6 A SIBERIAN SOLAR RADIO TELESCOPE ------------------------------ Daily, 5.72 GHz, Stokes I and V, 20 min time resolution, 21" spatial resolution. During flares: One dimensional scans of the full Sun disk with time resolution down to 14 ms (Stokes I and V). Two dimensional images of flare region with time resolution down to fractions of min. KITT PEAK --------- Regular full disk synoptic observations in the morning (1400-1700 UT -- photospheric and chromospheric magnetogram and 1083 nm spectroheliogram); high-rate chromospheric longitudinal magnetograms (rate depends on size of region). MARSHALL SPACE FLIGHT CENTER ---------------------------- Magnetograph--6x6 arcmin field of view with 3.2" resolution, taken in Fe I (5250.22 A), fastest cadence one magnetogram every 7 minutes (vector magnetograms and shear maps available on web). H-alpha-co-aligned with magnetograph, 1/2 A bandpass, 3 images per magnetograph image. Video rate recording is possible. MEUDON ------ In quiet periods: Full disk observations in H-alpha center line, +0.5 A and -0.5 A, with 1 min time resolution, 2" pixel size. During flares: H-alpha polarimeter; multichannel spectrograph with 9 simultaneous 2D channels, at 0.25 A resolution, with 8' x 5' field of view, 0.5" pixel size, 1 minute time resolution ALFRED UNIVERSITY H-ALPHA VIDEO SYSTEM -------------------------------------- Field of view 10x10 arcmin. H-alpha center line imaging at video cadence, using 0.6 A filter. RATAN 600 RADIOTELESCOPE ------------------------ Daily - 35 frequencies, 0.955-16.4 GHz, V and I Stokes parameters, 3 azimuths [near 8-00UT, near 9-00 UT (meridian time) and near 10-00 UT]; special alert program - several azimuths (up to 20 with interval 8-9 minutes of time) at the same equipment.