General description

Study of density fluctuations in the extended corona as a function of the outflow velocity of the solar wind while evolving in the heliosphere. If SPICE participates, will need to have limb pointing for a period of time, then return to disc centre for the full-Sun instruments.

Default SOOP duration: 8 hours. However,  a complete and detailed study of coronal density fluctuations requires a long temporal baseline (up to 24-30 hours). 

Pointing requirements: may require offpointing (e.g. limb)

Triggers: only IS triggers enabled 

Observations requirement (baseline)

SoloHI (lead)

Contributes with synoptic+shock+turbulence

modelled as 50% HI_SHOCK_PER + 50% HI_SYN_NEAR

disk center or stable pointing required. Fast cadence (1-min) radial subfields consisting of sums of multiple images.

Note: The exposure used in LTP9 were too short to provide sufficient SNR at those distances. The program is revised and a new version will be used in LTP11 with higher exposures and slighlt longer cadence (6 min).

Metis (lead)

FLUCTS for 1 hour:

(20 mins of: 60 x 1s DIT + 10mins processing x2
then 40mins at 20s cadence)

then MAGTOP (5 to 20 mins cadence)

Extra processing time is only needed at 1s cadence - 60 images can be stored and queend for processing

primary at perihelion: METIS SNR for 1s cadence + near corotation (8hours) (latitude changes not a big problem if ~1degree or less)
+ lower cadence during the rest of the window: several days min to observe the lower freq
duration: preferred to have it also 8h in the other 2 RSwindows


FSI Synoptic mode (S)

Deep exposures

Long exposures needed to get good SNR where it overlaps with Metis


 6-hr cadence

1024 x 1024

Ic, B, γ, φ

for context



SPICE currently proposes to use either SPICE Limb mode or SPICE Dynamics, depending on the target.


  • Slit: 4"
  • Exposure time: 5 s
  • X positions: 224
  • FoV: 15' x 11'
  • Nº repeats: 10
  • Observation time:
    • 18 mins per study
    • 3.2 hours total.

Active region (SPICE Dynamics) :

  • Slit: 4"
  • Exposure time: 60 s
  • X positions: 128
  • FoV: 8.5' x 11'
  • Nº repeats: 1?
  • Observation time: 2.1 hours
  • Limb active region target best if present. Cannot participate if Metis is observing, so not modelled for now.
  • If at limb: 224 positions of 60-s exposures, so lasting 4 hours; otherwise, the duration is as long as Metis requires.

Lines for SPICE Limb mode:

  • H I 1025 Å,

  • C III 977 Å,

  • O VI 1032 Å,

  • Ne VIII 770 Å,

  • Mg IX 706 Å,

  • Si XII 520 Å (2nd order) 

– 3 profiles and 3 intensities.

Lines for SPICE Dynamics:

  • 4 profiles and 6 intensities.

Science objectives

SAP objectiveTargetDurationOpportunity
(e.g., orbital requirements, solar cycle phase, quadrature ...)

Operational constraints 

Additional comments Study of density fluctuations in the extended corona as a function of the outflow velocity of the solar wind while evolving in the heliosphereDisc-centre to observe whole corona (except when SPICE observes at limb)8 hours x 3

1 8-hour observation in each RSW of an orbit

Good to have SPP in quadrature to observe the fluctuations in-situ. Energy and mass flux in the corona. Determine where energy is deposited in the solar wind What is the nature and origin of waves, turbulence and small-scale structures?

1.3.2 How is turbulent energy dissipated and how does turbulence evolve within the heliosphere?

Instances run / planned, differences from the baseline observations

With respect to the baseline observations requirements, Metis added to the FLUCTS_TBF mode (duration 1 hr) total brightness (tB)
observations with cadence of 1-2 min and duration of several hours, during both LTP9 and LTP11.


2022-10-12 to 13 (SOOP coordinators: Daniele Spadaro). 

Note: No density fluctuation detected with sufficient SNR for science analysis.


2023-04-12 to 14 (SOOP coordinators: Daniele Spadaro, Angelos Vourlidas)

Proposed SOOP Coordinators

D. Spadaro, A. Vourlidas, D. Berghmans, A. Giunta

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  1. SOOP ID in SOOP Kitchen = RF1