JOP 135 Filament Structure and Dynamics: H alpha Doppler, HeI and HeII Observations DATES: 20-24 December 2000, 16:00-23:00 UT or longer AUTHORS: Sara Martin - Helio Research Karen Harvey - Solar Physics Research Corporation Yi-Ming Wang - Naval Research Laboratory Jongchul Chae - Big Bear Solar Observatory Daniel Moses - Naval Research Laboratory SOHO TEAM CONTACT: Joseph Gurman ADDITIONAL COLLABORATORS: SOHO MDI - Emily Zamkoff UPDATE HISTORY: New proposal, Revised version December 11, 2000 PARTICIPATING SOHO INSTRUMENTS: EIT, MDI, LASCO COLLABORATING OBSERVATORIES and SCIENTISTS: Helio Research - Sara Martin Big Bear Solar Observatory - Jongchul Chae NSO/Kitt Peak - Karen Harvey Any others who wish to join SCIENTIFIC OBJECTIVE: The objective is to obtain data sets that will aid in better understanding the observed similarities and differences of prominence structure and dynamics in HeII 304A, HeI 10830A and Hydrogen alpha 6563A SCIENTIFIC JUSTIFICATION: Previous comparisons of prominences in HeII 304A and H alpha have shown large differences in the structure of the same prominences (Wang, H., Chae, J., Gurman, J. B., and Kucera, T. A. 1998: Comparison of Prominences in H alpha and He II 304, Solar Physics, 183, 91). Recent comparisons of images in HeII 304A and in H alpha have been made at Helio Research confirm that in many large differences in height and extent remain when H alpha images are taken with very long exposures. However, it is also found that some prominences are very similar in height and extent. A study is in progress using H alpha Doppler images at Helio Research during 1999 and 2000. The current study has a number of limitations. Among the daily EIT image sets, only one HeII 304 A image (typically at 19:19 UT), is recorded during the observing hours at Helio Research (16:00- 23:00 UT in winter). Hence only a few of the existing Helio Research prominence observations correspond closely in time to the 304A image at 19:19. Additionally, the Helio Research images have a limited field-of-view (7 X 7 arcmin.) Each day only one or two sets of H alpha Doppler images can be taken within a few minutes of the HeII 304A image at 19:19 UT. To carry the studies of HeII 304A relative to H alpha beyond these limitations, we propose special observing runs in which HeII 304A images are taken at a moderately high cadence one image per 12 minutes concurrent with ground-based observations in the western U.S. Over the 5-day interval, this would permit two types of studies: (1) the structure of selected major prominences and filaments taken once a day at nearly the same time at the western US sites along with the EIT observations and (2) the dynamics of one filament or prominence over many hours during each day at all participating sites along with the EIT and LASCO observations. . For the study of dynamics, the type of prominence selected at Helio Research, for the limited-field observations at collaborating observatories, will depend necessariy on the choices available on the Sun on the days designated for this JOP. The preferred targets for this part of the project will be: 1. a prominence or filament in the pre-eruptive or early eruptive state 2. prominence or filament in an activated state (with extensive Doppler shifts in excess of + and -0.6A 3. tall prominence with relatively open structure and large differences in height or structure between H alpha and HeII 304A. LASCO observations in the usual synoptic mode will be useful if the selected prominence or filament erupts. OPERATIONAL CONSIDERATIONS Target selection to be done by Helio Research and/or Big Bear Solar Obs. participants Observations at high cadence in HeII 304A outside of the window for the western US observatories 16:00-23:00 UT is at the discretion of the EIT planner. DETAILED OBSERVING SEQUENCES PER SOHO INSTRUMENT EIT 304A, cadence of 5 images per hour (one image every 12 minutes) for at least the hours of 16:00 to 23:00 UT each day.) LASCO in synoptic mode; no special request MDI: Minimum support is the synoptic 96 minute magnetograms. If practical, one minute full disk magnetograms while in high rate telemetry mode. DAILY OBSERVING PLANS FOR EACH GROUND-BASED TELESCOPE HELIO RESEARCH 1. On day before observations begin (19 Dec 2000): select prime target filament or prominences for observation and communicate this selection to observers at Big Bear, Kitt Peak and any other observatories which join this JOP Each day of Observing: 1. (a) Before first sunlight, review latest H alpha images and EIT 304A images available on the internet; designate each filaments and prominence for the once-a-day observation of structure; send this image and the coordinates of each filament/prominence to BBSO and Kitt Peak observers. 2. After opening telescope, if a filament or prominences is recognized to be in the early stage of eruption, begin Doppler movie immediately and communicate this information to the other ground-based observatories by telephone for coordinated observations. If an eruption is in the late stages, continue with next step 3. Take one or two sets of Doppler images of every major filament and prominence selected in (1) above. Allow 2 minutes for taking images on each subject and 1 minute for changing pointing to next subject. At Helio Research one set will consist of a series of H alpha images from +1.0A to -1.0A in at least 9 steps at 0.25A per step. If feasible, begin concurrently with Big Bear acquiring magnetograms of the same solar subjects in the same order. Weather permitting and in the absence of a current erupting event, this will be done during the time that the daily synoptic images are being taken with the vacuum solar telescope at Kitt Peak 4. Immediately after the survey of selected filaments/prominences is completed, begin taking observations of the one selected for the daily Doppler movie in H alpha. Can change target at this time based on the Doppler survey Helio Research. Confirm the prime target of the day with Big Bear and Kitt Peak and any other participating observatories with a limited-field instrument. HELIO RESEARCH DATA SPECIFICATIONS: IMAGE TYPES: H alpha time series from +1.0A to - 1.0A in steps of 0.25 A IMAGE AREA: approx. 420" X 420" IMAGE CADENCE: 5 sec at successive wavelength steps; minimum: 1 complete Doppler image set per 1 min or per 2 min. HOURS OF OBSERVATION: 15:30 - 23:00 UT. (flats before 16:00 UT if possible) BIG BEAR SOLAR OBSERVATORY 1. BBSO observers will perform same steps 2-4 above except using the Big Bear magnetograph and filtergraphs. IMAGE TYPES: digital photospheric magnetograms H alpha time series at centerline and +0.3 A and -0.3A CaII K line IMAGE AREA: approx. 300" X 300" IMAGE CADENCE: magnetograms, 1/min H alpha, 2/min. Ca K line 1/min. HOURS OF OBSERVATION: 16:00 - 00:00 UT KITT PEAK VACUUM TELESCOPE 1. Will take synoptic images as usual 2. When daily synoptic observations are completed, Kitt Peak observers are requested to begin a time series of images on the selected target to be communicated each day by observer at Helio Research. Specifications for the time series are: IMAGE TYPE: HeI 10,830A images unless weather is bad at Big Bear (BBSO); if BBSO is not observing, and if the target is not a prominence at the limb, the time series will be magnetograms (chromospheric if possible) instead of HeI images. IMAGE AREA: 512" N-S and 512" E-W or longer" as chosen by the observer to be large enough to include all of the target filament or prominence. IMAGE CADENCE: 1 image per 6 min. or multiple thereof to be as close as practicable to be similar to EIT HeII 304A cadence (1 image every 12 min). HOURS OF OBSERVATION: from the end of the daily synoptic observations to 23:00 UT as feasible. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Sara F. Martin sara@helioresearch.org Helio Research http://helioresearch.org 5212 Maryland Ave. Phone: 818-957-7507 La Crescenta, CA 91214 FAX: 818-957-7092 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<