SOT active region & flare observation plan

One of the SOT’s important tasks is to precisely measure magnetic field and velocity field configuration and their evolution, not only during the flare, but also before and after the flare for a long time as thoroughly as possible. Such measurements would help us to understand the physics involved in evolution of active regions and flares.

Due to the data telemetry limitation of Hinode spacecraft (〜4000Mbits/day), SOT cannot take high-cadence FG images, Magnetogram and SP data simultaneously for a long time. The SOT team needs to have some standard observation sequences dedicated to active region and flare observations, which will be mainly used when the Hinode observatory enters “active region & flare study” operation mode.

Here 4 observation programs are listed up as highest priority for active region and flare observations. By considering target size with the limited telemetry resource, 6 observation programs are designed as the initial programs. SOT-CO chooses one or some of these from the discussion with other COs at the planning.

· SOT-Case1-1: Active region, Topology – NLFF (Small)

Determine photospheric signatures of energy storage, trigger process that leads to flares and the coronal configurations of flare sites. The coronal magnetic field configuration is inferred by nonlinear force-free field calculation with photospheric magnetic field vector data. Chromospheric features can also help to infer the magnetic field lines.

	FOV	Cadence	Summing	Compress
SP: fast map	123”×123”	90 min	1-side	Q65
FG: Ca II H	109”×109”	2-3 min	2×2	Q50
FG: G-band	109”×109”	90 min	2×2	Q65
FG: Na D I/V	109”×109”	5 min	2×2
FG: H-alpha	109”×109”	90 min	2×2

Total data volume in 24-hour operation is 3,266 (3min) – 3,578 (2min) Mbits.

· SOT-Case1-2: Active region, Topology – NLFF (Large)

This is a same type observation program of SOT-Case1-1 for large active region.

	FOV	Cadence	Summing	Compress
SP: fast map	164”×164”	120-150 min	1-side	Q65
FG: Ca II H	164”×109”	120-150 min	2×2	Q50
FG: G-band	164”×109”	120-150 min	2×2	Q65
FG: Na D I/V	164”×164”	10 min	2×2
FG: H-alpha	164”×164”	120-150 min	2×2

Total data volume in 24-hour operation is 2,858 (2.5hr) – 3,515 (2hr) Mbits.

· SOT-Case2-1: Dynamics, long term evolution, thermodynamics (Small)

By observing long-term evolution of active region with high cadence, determine photospheric signatures of energy storage, trigger process that leads to flares and the coronal configuration of flare sites. This is a same type program of Case1 without SP and H-alpha images.

	FOV	Cadence	Summing	Compress
FG: Ca II H	109”×109”	1 min	2×2	Q50
FG: G-band	109”×109”	90 min	2×2	Q65
FG: Na D I/V	109”×109”	1 min	2×2

Total data volume in 24-hour operation is 2,904Mbits.

· SOT-Case2-2: Dynamics, long term evolution, thermodynamics (Large)

This is a same type observation program of SOT-Case2-1 for large active region.

	FOV	Cadence	Summing	Compress
FG: Ca II H	164”×109”	90 sec	2×2	Q50
FG: G-band	164”×109”	120 min	2×2	Q65
FG: Na D I/V	164”×164”	90 sec	2×2

Total data volume in 24-hour operation is 3,388Mbits.

· SOT-Case3: Active region on the Limb

Capture the temporal evolution of filament eruption as the trigger of flares and arcade structure of flares.

	FOV	Cadence	Summing	Compress
FG: Ca II H	109”×109”	30 sec	2×2	Q50
FG: G-band	109”×109”	90 min	2×2	Q65

Total data volume in 24-hour operation is 3,768Mbits.

· SOT-Case4: Impulsive phase of Flare (Flare mode)

Study the chromospheric evaporation and particle acceleration process during the flare. Identify the foot-point of the flare loop precisely and observe its motion during the flare, and also observe white light flare.

(During the “Flare mode” by XRT)

	FOV	Cadence	Summing	Compress
FG: Ca II H	109”×109”	20 sec	2×2	Q50
FG: G-band	109”×109”	20 sec	2×2	Q65
FG: Red	109”×109”	20 sec	2×2	Q65
FG: Green	109”×109”	20 sec	2×2	Q65
FG: Blue	109”×109”	20 sec	2×2	Q65
FG: H-alpha	109”×109”	20 sec	2×2	Q65

Total data volume in 20-min operation is 567Mbits.