HOP 0451

proposer

name :

Mihailescu, Baker, De Pontieu, Long, Green

e-mail :

teodora.mihailescu.19[at]ucl.ac.uk, deborah.baker[at]ucl.ac.uk, bdp[at]lmsal.com, d.long[at]qub.ac.uk, lucie.green[at]ucl.ac.uk

abstract of observational proposal

Main Objective: Tracking the coronal composition (using Hinode EIS) and plasma temperature at chromospheric heights (using IRIS) in the leading and following polarities of an active region over a few days.

Scientific Justification: Plasma composition (quantified using the FIP bias parameter) was found to be correlated to photospheric magnetic flux density (Baker et al., 2015; Mihailescu et al., 2022). Mihailescu et al. (2022) suggest that changes in magnetic flux density influence the plasma temperature at chromospheric heights which in turn influences the amount of ionized low FIP elements at those heights. This then has a direct impact on the FIP bias we measure in the corona.

The proposed IHOP observations aim to test this idea by tracking an active region over a few days and simultaneously measuring its photospheric magnetic field (using SDO HMI), plasma temperature at chromospheric height (using IRIS) and coronal plasma composition (using Hinode EIS). Active region leading polarities tend to have more concentrated magnetic field than their following counterparts - we request tracking both polarities to cover a wider range of magnetic flux values.

request to EIS

Indications:
1) one scan of the leading polarity followed immediately by one scan of the following polarity
2) ideally, repeat both scans every 12 hours for 4-5 days, but 1 set of observations per day is acceptable

Observations: Atlas_60 (ST_ID: 404, FOV: 120''x160'', exp: 60s, dur: 60 minutes)

other participating instruments

Indications: follow EIS pointings (one scan of the leading polarity followed immediately by one scan of the following polarity at the same times as the EIS scans; repeat both scans every 12 hours/24 hours for 4-5days)
Observations: 3600108077 | Very large dense 320-step raster 105.3x175 320s Deep x 8 Spatial x 2 | 2946.32 | 2476.28 | 0.57 | 9.2+/-0.1 | 2946+/-0 | 36.8+/-0.0 | 36.8+/-0.0 | 36.8+/-0.0 | 36.8+/-0.0 (FOV: ~120”x170”, dur: 49 minutes)

Note: Proposal submitted to and selected by the IRIS team

remarks

Dates: ToO

Time window: N/A

Target(s) of interest: Active region East of central meridian, with at least one sunspot. EIS and IRIS to take co-temporal and co-spatial observations of the leading and following polarities.

Additional instrument coordination: None

Previous HOPs: No prior HOP submissions.