HOP 0414

proposer

name :

French, Landi, Matthews, Brooks, del Zanna, Valori

e-mail :

ryan.french.14[at]ucl.ac.uk, elandi[at]umich.edu,
sarah.matthews[at]ucl.ac.uk, dhbrooks.work[at]gmail.com, gd232[at]cam.ac.uk, g.valori[at]ucl.ac.uk

abstract of observational proposal

Main Objective: Combine measurements from EIS with magnetic field extrapolations to track the evolution of the magnetic field in an active region.

Scientific Justification: The detailed structure and evolution of the coronal magnetic field remains one of the most poorly constrained parameters in solar physics, and yet is key to understanding energy release and transport in the outer atmosphere. Recent developments by Si et al. (2020) and Landi et al. (2020) have demonstrated the important new possibility of measuring the coronal magnetic field though exploitation of the magnetically induced transition of the Fe X 257.26 A line which lies within the EIS long wavelength range. The technique has already been successfully applied to several active regions, including one which produced a C-class flare (Landi et al., 2021). The goal of this project is to build on these initial results to provide detailed mapping of the coronal field evolution in space and time by combining coronal magnetic field maps from EIS with field extrapolations that use HMI data as the input. Supporting SOT and IRIS observations will provide detailed information on photospheric field and chromospheric evolution, while XRT will provide additional context both for constraining the extrapolations and interpreting the EIS observations.

request to EIS

If the likelihood of flaring is high please target the neutral line in the core of the active region and run the following studies:
- run el_dhb_01 repeatedly for 4-6 hours; if telemetry useage makes this difficult to accommodate, use el_dhb_02 which is a lower telemetry option
Studies are:
el_dhb_01:
ST_ID: 602, FOV: 50"x152", Exp.: 10s, Dur.:5m34s
el_dhb_02:
el_dhb_02:
ST_ID; 603, FOV:50”x152”, Exp.: 10s, Dur.: 5m 34s

If activity is low and flaring is unlikely please run:
ST_ID 361: CAM_AR_LIMB_LITE_V2 -- exposure time 45s with 323"x376" FOV

other participating instruments

IRIS requests:
As for IHOP 409, we request -

High data rate:
Large sit-and-stare 8 sec cadence, C II Si IV Mg II h/k slit jaws
3660259103 | Large sit-and-stare 0.3x120 1s C II Si IV Mg II h/k Deep x 8 FUV | 28.26 | 38.06 | 0.92 | 9.4+/-0.1 | 9.4+/-0.1 | 28.3+/-0.0 | 28.3+/-0.0 | 28.3+/-0.0 | 0.0+/-0.0

Low data rate:
3660259102 | Medium sit-and-stare 0.3x60 1s C II Si IV Mg II h/k Deep x 8 FUV | 28.14 | 15.92 | 0.39 | 9.4+/-0.2 | 9.4+/-0.2 | 28.1+/-0.0 | 28.1+/-0.0 | 28.1+/-0.0 | 0.0+/-0.0

If rolls are allowed, adjust roll angle so that the slit is perpendicular to the neutral line. This is to be repeated for the 4-6 hour HOP period, to be coordinated with Hinode.

In addition to this, we request a large-scale scan before & after each observing run.
3620106078 | Very large dense 400-step raster 131.7x175 400s Deep x 4 Spatial x 2 | 2071.70 | 2564.81 | 0.84 | 5.2+/-0.1 | 2072+/-0 | 20.7+/-0.0 | 20.7+/-0.0 | 20.7+/-0.0 | 20.7+/-0.0

remarks

Dates: 23 - 29 March 2021

Time window: 4-6 hours minimum each day to provide coverage of the active region evolution. If possible, and the target has a high probability of flaring, then longer would be desirable. Interruptions for synoptic observations are fine.

Target(s) of interest: Active region on disk. The target will be chosen in the first instance based on proximity to disk centre (for the extrapolations) and second, based on likelihood of flaring activity.

Previous HOPs: HOP 375 (no suitable target for SST); HOP 399