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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0415

A holistic view on coronal holes - overview scans

plan term


@ @


 name : Hofmeister @  e-mail : stefan.hofmeister[at]columbia.edu

contact person in HINODE team

 name : Savage, Watanabe, De Pontieu @  e-mail : sabrina.savage[at]nasa.gov, watanabe.tetsuya[at]nao.ac.jp, bdp[at]lmsal.com

 abstract of observational proposal
Scientific Justification * We organize an observing campaign to build a holistic view of the solar source coronal hole of the high-speed solar wind stream seen by Parker Solar Probe (PSP) at its 8th perihelion on April 29th. This campaign will address the following questions:

-  Where are the individual open magnetic funnels which build the coronal hole rooted?
-  How is mass transported from the photosphere to the corona in these funnels? -  How does the outflow velocity and mass flux in the lower corona in coronal holes depend on the properties of the open magnetic funnels in lower atmospheric heights?
-  How do the solar wind properties seen by PSP depend on the properties of its source coronal hole?
-  How does the associated high-speed solar wind stream evolve from the Sun to 0.9 AU as seen by Solar Orbiter and 1.5 AU as seen by Maven?

The time window around Parker Solar Probefs (PSPs) 8th perihelion provides a unique opportunity to address these questions, as the perihelion is observable from Earth view, as it takes place end of April where usually the observing conditions for the ground-based telescopes in Tenerife are good, and as Solar Orbiter and Maven are well aligned with PSP. The observing campaign will be 10 days, i.e., from April 28th to May 7th , with an observing time of roughly 4.5 hours per day.

We received SOLARNET observing time for the ground-based high-resolution spectropolarimetric instruments SST/CHRISP and GREGOR/GRIS. They will probe and create magnetic field maps from the photosphere to the upper chromosphere in 4 heights, which shall allow us to uniquely identify the open magnetic funnels in coronal holes. Here, we request IRIS and Hinode for observations of the transition region and corona to study the plasma outflow velocity, temperature, density, mass flux, and FIP abundances in multiple heights.

The IRIS and Hinode observations during these 10 days shall be performed in two setups:

ESetup #1: detailed scans over entire coronal holes at multiple days, in order to study the distribution of magnetic funnels and their statistical properties, and their long-term evolution.
ESetup #2: high-cadence scans of subregions of coronal holes at the other days, in order to study the short-term evolution and upward propagating waves from the photosphere to the low corona.

In order to maximize the output of this observing campaign, we coordinate this observing campaign with the Whole Heliosphere and Planetary Interaction (WHPI) initiative, and expect that further ground-based optical and radio observatories join the effort. To ease the collaboration, all of the data taken shall be publicly released immediately after the observations. This proposal covers Setup #1 of the campaign.

 request to SOT
SOT/SP shall perform a single fast scan over a region of 320hx164h within the coronal hole. Amount of data: ~1 Gigabit for the entire scan. Duration: ~1 hour. In case of insufficient telemetry for SOT, these scans can be skipped at some days.

 request to XRT
XRT shall take 512hx512h observations, alternating the thin-Be filter (exposure time: 32 seconds) and the Al-poly/Ti-poly filter (exposure time: 12 seconds), at a cadence of 4 minutes.

 request to EIS
EIS shall scan the entire coronal hole including its nearby boundary region, using multiple tile windows of 130hx512h. The individual tile windows shall use the study definition CH_funnels+FIPv2, and be performed outside SAAs.

Size: ~37.5 Mbyte x n_tile_windows

Line lists:
Line list: Line(s) Central wavelength (A)
S X 180.53
O VI 184.05
Fe XII 186.75
Fe XI 188.53
Fe X 189.87
S XI 191.27
Ca XVII 192.82
Fe XII 193.54
Fe XII 195.12
S VIII 198.55
Fe XIII 203.40
O V 249.29
He II 256.32
Fe X 257.75
Si X 261.04
S X 264.23
Mg VI 269.05
Mg VI 270.40
Si VII 272.65
Si VII 275.97
Mg VII 278.39
Mg VII 280.15
Fe XV 284.16

 other participating instruments
IRIS: Shall scan the entire coronal hole by multiple mosaic cells distributed over the coronal hole. The exact number of mosaic cells depends on the size of the coronal hole, but will be likely 3x3. The coordinates of each mosaic cell will be provided by the PI.

The planner is free to choose one of the following observing IDs, depending on the downlink rate available:

3821854096  (Very large dense raster 131.7x175 400s Deep x 2 Spatialx2 Spectralx2 FUVx8) . Data rate: 0.6 Mbit/s.

3821834096  (Very large dense raster 131.7x175 400s   Deep x 2 Spatial x 2, Spectralx1 FUVx8) Data rate: 1.0 Mbit/s.

3821754096  (Very large dense raster 131.7x175 400s Deep x 2  Spatialx1 Spectralx1 FUVx8) . Data rate: 1.97 Mbit/s.

Additional instrument coordination: GREGOR and SST

Dates: 10 days of observations, from April 28th to May 7th . The observations shall be coordinated with IRIS, GREGOR and SST.  The assigned observing time within the 10 days is shared with the IHOP A holistic view on coronal holes - temporal evolution, whereby on each day only one of the two IHOPs will be run.

Time window: Shall be arranged with GREGOR and SST, preferable starting at/before 7:30 am UTC. The time window has to allow to scan an entire coronal hole. For this, likely three consecutive observing slots outside SAAs will be needed, depending on the size of the apparent coronal hole.

Target(s) of interest: Low-latitude coronal hole, or low-latitudinal extension of a polar coronal hole, respectively.

Previous HOPs:
IHOP 400, which was performed on 23rd October, 2020. This IHOP was a test run for the now proposed campaign. We are currently working on the data, which lead to the updated line list and observing program as proposed above.

Additional remarks:
Due the large EIS data amount, we request the limb-mode allocation for Hinode/EIS.

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