HOP 0392

abstract of observational proposal

Main Objective: Measuring plasma parameters at a coronal hole boundary to investigate how solar wind near the heliospheric current sheet is released, in support of Parker Solar Probe’s 4th perihelion.

Scientific Justification: The Parker Solar Probe (PSP) spacecraft hosts two electron electrostatic analysers (SPAN A and B), which provides derived electron density, velocity and temperature measurements. The analogue to these measurements may be obtained remotely by observing potential source regions using Hinode EIS.

We propose target selection to be based upon the predicted magnetic connectivity of PSP to the corona. This will be predicted using a model of the solar atmosphere and early solar wind evolution, as shown in Stansby., et al. 2019b (doi:10.3847/2515-5172/ab13b7). This model can be used to forecast likely connectivity in advance and has done so successfully for previous perihelia.

Studying the properties displayed by the connected solar atmosphere and its different regions (inside the coronal hole and at the boundary) will allow for direct comparison of electron parameters with measurements of the early solar wind that PSP will be taking.

request to EIS

4.1 Case of coronal hole scan

STUDY: Large Coronal hole study
STUDY_ID: 453
RASTER: HOP177_CH
SLIT: 2”
STEP_SIZE: 3”
EXPOSURE_TIME: 60s
LINE LIST:
FeX 184.36
FeVIII 185.21
FeXII 186.80
FeXI 188.26
CaXVII 192.82
FeXII 195.10
FeIX 197.86
SVIII 198.55
FeXIII 202.04
FeXIII 203.83
HeII 256.32
FeX 257.26
FeXVI 262.98
MgVI 268.99
SiVII 275.35
MgVII 278.39
OIV 279.93
MgVII 280.72
FeXV 284.16

POINTINGS:
Contact David Stansby (d.stansby@ucl.ac.uk) when this version is run in order to provide target position.

REMARK:
The duration of each scan is around 1 hour. We request repeated scans of target region. The IRIS team has agreed to support the IHOP. If coordination is not possible, we suggest the EIS scan should be run
anyway.

4.2 Case of active region scan
STUDY: HPW021VEL360x512v1_b
STUDY_ID: 523
RASTER: HPW021VEL360x512v1_b
SLIT: 1”
STEP_SIZE: 2”
EXPOSURE_TIME: 60s
LINE LIST:
Fe XI 180.40
Ca XV 182.10
Fe X 184.33
Fe VIII 185.21
Fe XII 186.75
Fe XI 188.40
Ca XVII 192.47
Ca XIV 194.10
Fe XII 195.12
Fe IX 197.86
Ca XV 201.05
Fe XIII 202.04
Fe XIII 203.83
Ca XVI 208.50
Fe XXIV 255.00
S XIII 256.48
Si X 258.37
Fe XVI 262.98
S X 264.30
Fe XIV 270.52
Si VII 275.40
Mg V 276.30
Mg VII 278.40
Mg VII 280.39
Fe XV 284.16

POINTINGS:
Contact David Stansby (d.stansby@ucl.ac.uk) when this version is run in order to provide target position.

REMARK:
The duration of each scan is around 3 hours. The IRIS team has agreed to support the IHOP. If coordination is not possible, we suggest the EIS scan should be run anyway.

other participating instruments

IRIS requests:
INDEPENDENT OF CASE STUDY:
High datarate version: 3620259477 | Very large dense 320-step raster 105.3x175 320s Si IV Mg II h/k Dee | 3028.32 | 6277.94 | 1.4 | 9.5+/-0.2 | 3028+/-0 | 0.0+/-0.0 | 18.9+/-0.0 | 18.9+/-0.0 | 0.0+/-0.0

Low datarate version: 3600109477 | Very large dense 320-step raster 105.3x175 320s Si IV Mg II h/k Dee | 2960.64 | 2476.28 | 0.6 | 9.3+/-0.1 | 2961+/-0 | 0.0+/-0.0 | 18.5+/-0.0 | 18.5+/-0.0 | 0.0+/-0.0

Point of Contact:
Contact Bart De Pointieu (bdp@lmsal.com) and Magnus Woods (woods@baeri.org) to provide pointings

remarks

Dates: ToO.
When the Parker Solar Probe footpoint is within the prime HMI field of view: Approximately ±60 degrees from disk center in the East-West direction. This is predicted to be between the 25th of January and the 30th of January 2020 as per the current results of the connectivity model: see https://www.davidstansby.com/PSP/pfss/orbit4.html.

Observation Continuity: Multiple sets of scans across the five-day period would be beneficial for the science study, for example one at the start, one in the middle, one at the end. It is not necessary to get observations in consecutive days, and the study can be interrupted. Time window: Minimum duration is case-dependent.

The Coronal Hole case uses a 1 hour scan, with a set of three per allocated observation being preferable.

The Active Region case uses a 3 hour scan.

Target(s) of interest: The main science case for this Observation Programme is the case for a Coronal Hole Scan. In the case of an active region emergence (likely to be seen in STEREO-A in advance), the second Case should be followed.

Previous HOPs: No prior HOP submissions

TIME PERIOD: Repeated scans are ideal, as we will be assuming time steady state conditions on both the coronal hole and its boundary.

TIME WINDOW: When the Parker Solar Probe footpoint is within the prime HMI field of view: Approximately ±60 degrees from disk center in the East-West direction. This is predicted to be between the 25th of January and the 30th of January 2020 as per the current results of the connectivity model: see https://www.davidstansby.com/PSP/pfss/orbit4.html.

TARGET: Coronal Hole and Coronal Hole boundary near relevant magnetic footpoint as informed by points of contact.

OTHER: Multiple sets of scans across the five-day period would be beneficial for the science study. IRIS OBSIDs use 8 seconds exposure time, which makes them suitable for both active regions and coronal holes.