SOTSP: HOP 191 with BBSO / NST
2011-07-12T19:21:00 to 2011-07-12T19:37:00
Science Goal: Observations of the Chromosphere Coordinated with BBSO/NST
Program: Fast map 82x82", 1 side Q75
Target: Active Region
xcen=235 ycen=91
Instrument: SOTSP
HOP/JOP: 191
Description:
Request to SOT HOP Number 0188 We request that SOT run a modified version of Case Study #4, to study the impulsive phase of flares: 109"x109" FOV in Ca II H, G-band, and red, green and blue continua at 60 second cadence. The H-alpha line is omitted from this version due to the degradation of the filter. The cadence is reduced to 60 seconds as ROSA itself will be looking at similar wavelengths at its own ultra-high cadence
this will free up more bandwidth for EIS. SOT data will be primarily used for co-alignment purposes, but this dataset should still provide sufficient science quality data in the event of unfavourable weather at the DST. SOT = 150 Mbits / 20 minutes = 1800 Mbits for 4 hours. Other Instruments: ROSA: Ca II K, H-alpha, 3500 and
4170 continua, Fe I magnetograms, G-band (0.03s cadence, 70"x70" FOV) IBIS: Na D1 Dopplergrams, Ca IR triplet (2-20s cadence, 85"x85" FOV) SDO/EVE: MEGS-A (6-37nm
incl. He 304A line), MEGS-B (37-105nm
incl. H + He continua), MEGS-P (Lyman-alpha) (10s/0.25s cadence, sun-as-a-star observations) (N.B. EVE have agreed to change their daily 3-hour MEGS-B and MEGS-P campaigns from 05:50-08:50 UT to 14:30-17:30 UT to coincide with the ROSA observing schedule). SDO/AIA: AIA will be included in play, taking high-resolution images in each of its 8 filters at 12s cadence. RHESSI: RHESSI will be included in play, taking full-disk HXR observations each orbit. SOHO/CDS: We wish CDS to run the FLARE_AR observing sequence, which comprises the He I, O V, Mg X, Fe XVI and Fe XIX lines. (~11 minute raster cadence, 180"x180" FOV). ISOON: H-alpha core (60s cadence, full Sun) Scientific Objectives: The scientific goal of this study is to determine the chromospheric response to nonthermal electrons, at multiple wavelengths simultaneously, during the initial stages of solar flares. The chromosphere is the primary radiating source during flares, with the majority of flare energy emerging in the form of optical/UV lines and continua. This radiation is believed to be driven by electrons (and possibly ions) accelerated during flares, and provides a crucial diagnostic for the energy deposition. The chromosphere is also the location of hard X-ray footpoint sources and
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the bremsstrahlung emission that is the diagnostic for the nonthermal electrons, and thus a major clue to the fundamental process of particle acceleration and flare energization. The chromosphere is also understood to be the source of the hot, dense plasma that causes the dramatic brightening in coronal flare loops through the process of chromospheric evaporation. The radiative hydrodynamic model of Allred et al. (2005) provides one of the most comprehensive simulations of chromospheric heating by relativistic electrons to date. This model predicts a specific response of both line and continuum emission on sub-second timescales to varying parameters of injected electron beams. The ROSA instrument is now able to image the solar atmosphere on these intrinsic timescales. It is a common user instrument at the Dunn Solar Telescope (DST) in Sunspot, New Mexico and incorporates 6 cameras, each synchronised to 50 microseconds, with filters in Ca II K, H-alpha, 3500 and 4170 continua, G-band, as well as the Fe I line. From the data obtained by this HOP we aim to undertake a thorough investigation of the flaring chromosphere, including the origin of white light emission, by comparing co-ordinated observations from ROSA, IBIS, Hinode, RHESSI, SDO, and other GBOs, with theoretical predictions.
