------------------------------------------------------------------------ * Title of the proposed observation: Physical mechanisms driving solar microflares and network dynamic fibrils - relevance for coronal heating and mass supply (small update of the previously run HOP020) * Short statement describing the observation, and scientific justification. This proposal merges together attempts to observe two kinds of solar structures - solar microflares and network dynamic fibrils - which are planned to be investigated to address common open questions on their relevance for the heating and dynamics of the solar corona. Due to their small sizes and fast dynamics microflares need analysis demanding high spatial resolution observations combined with good temporal cadence. Our objective is to analyse the dynamics and plasma evolution during microflares by studying the chromospheric response to electron beam and/or conductive heating together with the transition region and coronal response combined with X-ray spectral analysis. The comparison of these observational data with theoretical predictions in the frame of electron-beam-driven and conductively driven chromospheric evaporation for individual microflares can help us to answer several open questions regarding microflares and the coronal heating. Network dynamic fibrils (DFs) display in the chromosphere repetitive mass loading by acoustic shocks driven by the global oscillations in the underlying photosphere. This scenario assumes that considerable power of photospheric 5-min oscillations is concentrated at the bases of inclined magnetic fluxtubes giving rise to the chromospheric DFs. Using H alpha filtergrams obtained by the Dutch Open Telescope we have shown that the DFs exhibit also significant variations in orientation, which are faster for shorter DFs. Recently, downflows and upflows occurring at the base and tops of mottles, respectively, were reported. To explain this dynamic structure the magnetic reconnection as a potential driver of mottles was suggested. As an extension of the works mentioned above, in this proposal we aim at identification of the center-to-limb variation of kinematic properties of dynamic fibrils and also center-to-limb variation of terminal wavelength shift of visibility of the fibrils and mottles in the H alpha line profile. Thus, the spectral observations of chromosphere with the best, spatial and spectral resolution, are needed. More details: campaign page: http://www.astro.sk/~choc/open/08_dot/08_dot.html * Point of contact: Jan Rybak, Astronomical Institute, Slovak Academy of Sciences Tatranska Lomnica, Slovakia (choc@astro.sk, www.astro.sk/~choc) * Time period of proposed observations: o period: 6-20/10/2008 - this is the period for which we were granted by the DOT/LaPalma observing time (OPTICON time) o the minimum number of observation days during the period: none o Requirements for continuity of observations: it is not necessary for observations to be on consecutive days * Time window in day: o minimum: start and end times: 08:00-12:00 UT o optimum: start and end times: 07:00-13:30 UT coordination with the DOT/LaPalma ground-based and SOHO+TRACE JOP 189 space-based observations o short interruptions are allowed over the observing period * Target of interest: o target of interest: microflares: active region on-disk near the disk center or their remnants network fibrils: quiet Sun on-disk near the disk center o target will be specified well in advance depending on the actual solar activity o chance to have the target: we expect that our second target can be observed each day due to the regular appearance of the network at the disk center o target of opportunity (TOO): no * Required Hinode instruments, and priority of observables: o Hinode instruments really required for the observations: EIS,SOT,XRT o Specify required observables: Hinode/SOT: - FOV: 55" x 111" (512 x 1024 pxs, binning: 2 x 2 pxs) - spectral channels: sequentially in time BFI: G-band, Ca II H - cadence: 32s per filtergram (64s per sequence of 2 selected channels) - total run duration: 4.0 hours (08:00-12:00 UT) - minimum 5.5 hours (07:00-13:30 UT) - optimum - compression: JPEG Q75 - telemetry needed: minimum - 4.0 hours: ~520 Mbits optimum - 6.5 hours: ~845 Mbits estimated according the tables at http://solar-b.nao.ac.jp/sot_e/operation/ further possible decrease of telemetry load: slower cadence, smaller FOV - compensation of the solar rotation, x=0 at 10 UT - pointing: around the position of the EIS 1D sit-and-stare mode slit Hinode/XRT: - high cadence images using just one selected filter - 256x256 px, no binning - exposure time: max. 15s with AEC, the highest possible cadence limited by the available telemetry - filters: microflares: thin Be filter, network fibrils: thin-Al/Mesh - low-less compression - compensation of the solar rotation in the way that x=0 at 10 UT - pointing: disc center or near disk center Hinode/EIS: STUDY TITLE: Solar microflares and network dynamic fibrils - relevance for coronal heating and mass supply TARGET/POINTING: 1/ quit sun at the disk center or alternatively 2/ an AR (or its remnants) near the disk center EXPOSURE TIME: 10s SLIT: 2" COMPRESSION: JPEG90 Number of studies: 2 1/ Study dot+eis:mic_fib_con: scanning, step size: 2", FOV: 44"x120" 2/ Study dot+eis:mic_fib_sit: sit-and-stare, FOV: 2"x120" USE/INSTRUCTIONS TO PLANNERS: STUDY NAME RASTER NAME dot+eis:mic_fib_con: consisting of only one raster Context_calib_jr_08 dot+eis:mic_fib_sit: consisting of only one raster Obs_sit_stare_jr_08 C. Ordering of the studies (with no. of repeats) : STUDY RASTER Repetition Time Total time 1. dot+eis:mic_fib_con Context_calib_jr_08 1 times 4m50s - number of study repetitions: 3, total time: 14m30s 2. dot+eis:mic_fib_sit Obs_sit_stare_jr_08 1 times - 10m - number of study repetitions: 11, total time: 1h50m - slit placed to the X-center of the previous rasters 3. dot+eis:mic_fib_con Context_calib_jr_08 1 times 4m50s - number of study repetitions: 3, total time: 14m30s - raster positioned at the previous slit position There could be an interruption between the previous and following study allowing any instrument specific upload of tables, etc. 4. dot+eis:mic_fib_con Context_calib_jr_08 1 times 4m50s - number of study repetitions: 3, total time: 14m30s 5. dot+eis:mic_fib_sit Obs_sit_stare_jr_08 1 times - 10m - number of study repetitions: 11, total time: 1h50m - slit placed to the X-center of the previous rasters 6. dot+eis:mic_fib_con Context_calib_jr_08 1 times 4m50s - number of study repetitions: 3, total time: 14m30s - raster positioned at the previous slit position Total time: 2 x 2h19m (Data volume: 2 x 51.23 MBits) PREFERRED OBSERVING TIME SLOT (~DOT/LaPalma): ~09 - ~13 UT PREFERRED POINTING (~DOT/LaPalma): if disk center: then to have x=0 at 10UT while compensating for solar rotation SCHEDULING OF THE PROGRAM: Program is prepared according new study Submission requirements. The planner is free to change number of repetitions of the study 2. and 5. in the ordering of studies above in order to allow an optimum interruption of the program due to instrument specific uploads, etc. Nevertheless we would extremely welcome if our program can be run in the preferred observing time slot (09-13UT). Predicted count rates: Active region/Quiet sun - 10s. Note: we expect higher count rates than counts obtained for the quiet sun listed below when observing the network emission. Wavelength c/p Ion Total counts for exposure (per pixel) active region / quiet sun 192.82* c Ca XVII 572 / 0 195.12* c Fe XII 4240 / 138 256.32* c He II 247 / 47 186.88 p Fe XII (the spectral window selected to cover also 186.00 Fe VIII line) 263.76 p Fe XXIII ------------------------------------------------------------------------