General description

Science Goal: What are the release mechanisms of the slow solar wind at an open-closed magnetic field boundary? (See Slow Wind SOOP slides)


  • Link in-situ plasma to specific coronal source regions,
  • Observe the magnetic field configuration and its evolution at open-closed boundaries
  • Identify possibly signatures of interchange reconnection at open-closed boundaries

Target: active region/coronal hole boundary, dependent upon magnetic connectivity

Default SOOP duration: 3 days

Pointing requirements: Off-pointing: specific target pointing or target tracking 

Triggers: only IS triggers enabled

Observations requirement (baseline)



close mode + scheduled/triggered burst



normal + scheduled/triggered burst

Low-latency data useful

RPWRPW_NORMAL_HIGH1normal + scheduled/triggered burst

normal + scheduled/triggered burst

Low-latency data useful


Combination of:


Raster area should be optimised to make sure open-closed field boundary is captured

Line choices optimized for type of target

Run combination of:

- spectral atlas, full spectrum, FOV=2’x11’, duration ~53 minutes

- A composition map, 60 s exposure time, FOV=10.6’x11’, duration of 2.7 hours, lines included:

O III 70.3 nm multiplet
Mg IX 70.6 nm
S IV 75.0 nm
N IV 76.5 nm
Ne VIII 77.0 nm
Mg VIII 77.2 nm
S V 78.6 nm
O IV 78.7 nm
C III 97.7 nm
O VI 103.2 nm

- slow dynamic study (synoptic type), 30 s exposure time, FOV=12.8’x11’, duration of 1.6 hours, 5/6 repetitions of this study according to the time available and spacecraft constraints (e.g. WOLs, HGA_PT), spectral lines included:

O III 70.3 nm multiplet
Mg IX 70.6 nm 
O II 71.8
O V 76.0 nm multiplet
N IV 76.5 nm
Ne VIII 77.0 nm
S V 78.6 nm
O IV 78.7 nm
C III 97.7 nm
H I 1025 nm
O VI 1032 nm


EUV & LYA Coronal hole modes (C) (uses HRI) at 6s cadence

FSI Synoptic mode (S) throughout at 900s

If TM is limited, varying priority schema can be used to keep HRI data manageable



Regularly spaced HRT data at medium to high resolution (~3-5 mins) e.g.


+ regular PHI_synoptic_4

PHI LL magnetograms needed throughout.
Note that 1 hour cadence can suffice for interchange reconnection at high resolution. 

Processing after the RSW: PHI could focus downlink on the most interesting periods, as inferred from other LL data



for context and linkage of solar wind source regions to SC 

Only applicable if beyond ~0.5AU during target tracking



Context via SoloHI synoptic modes


not strictly needed for SOOP although context is appreciated

Science objectives

SAP objectiveTargetDurationOpportunity/Orbital configuration

Operational constraints 

Additional comments Does slow and intermediate solar wind originate from coronal loops outside of coronal holes? coronal loops outside of coronal holesfew days
  • near perihelion for resolution & better linkage conditions
  • different phases of solar cycle
  • radial alignment with SPP is a plus
  • it may be worthwhile to map around the whole AR to have higher chance of being connected
  • EMC quiet for connectivity

radial alignment with SPP is a plus Study fast plasma flows from the edges of solar active regions discovered with Hinode/EISedges of solar active regions - at most likely ballistic connection pointfew hours 
  • radial alignment with SPP is a plus
  • fast flows require high cadence observations (mainly SPICE and HRI?)
radial alignment with SPP is a plus Interchange reconnection between open and closed field lines and its role in slow wind generation

Open-Closed field line boundaries (near ballistic connection point):

  • CH boundaries
  • AR edges close to low-latitude open field
  • Intermediate areas of quiet Sun

Target tracking

~1 RSW (10 days)
  • to be studied for CHs in different locations (high vs low latitudes)
  • different opportunities along the orbit: high-latitude windows + perihelion
  • to be studied in different solar cycle phases
  • Earth view before the observations would be asset to use modelling to define best target
  • radial alignment with SPP is a plus
  • During RSW
  • pre-window synoptics needed for target choice
  • VSTP updates needed for target tracking
  • EMC quiet for connectivity
radial alignment with SPP is a plus Magnetic reconnection in the chromosphere, the transition region and the corona

Quiet Sun at various latitudes.several dayslow + high latitue, to be repeated along the cycle
  • during RSW
  • feature tracking

Only PHI, EUI/HRI and SPICE really necessary for this goal.

PHI/HRT mode 2 with 5-10 min cadence, 5 quantities and no binning

EUI/HRT follows cadence of PHI

Instances run / planned

LTP6 (run): 

2022-03-03 to 06, 2022-03-17 to 22 (SOOP Coordinators: S. Yardley)

The slow wind connection SOOP operated with the baseline observations outlined above.

LTP11 (planned)

2022-03-30 to 04-02, then 2023-04-22 to 04-24 (SOOP Coordinators: S. Yardley, A. James)

Science outcomes

Yardley et al. (2022, in prep): Slow Solar Wind Connection Science during Solar Orbiter’s First Close Perihelion Passage

Ngampoopun et al. (2022, in prep): Southern Polar Coronal Hole Boundary: Investigating the eruption of a filament channel and its merging with the southern polar coronal hole


Baker et al. (2022, in prep): Observational Evidence of S-web Source of Slow Solar Qind

Berghmans et al. (2022, in prep): First Perihelion of EUI

Further information

(see Yardley et al. 2022, in prep)

RSW1 Target: NOAA active region complex including ARs 12955, 12957, 12961

RSW2 Targets:

  • Southern polar coronal hole boundary (2022-03-17 06 UT – 2022-03-18 18:40 UT)
  • NOAA AR 12967 (2022-03-18 18:40UT – 2022-03-22 00UT)

Coordinated Observations: Hinode and IRIS through IHOPs 433 and 434.

Original SOOP proposers

C. Owen, Hardi Peter, Tim Horbury, Pradeep Chitta (Obj 4), D. Spadaro, A. Giunta, L. Harra, D. Baker

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  1. Anonymous

    (Andreas Lagg): This SOOP also covers the scientific plan proposed by Hardi Peter: "Solar wind variations on supergranular scales"

  2. SOOP ID in SOOP Kitchen = LS2