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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0381

Observations for inferring the plasma beta parameter in different Quiet Sun regions

plan term


@ @


 name : Palacios, Rodriguez Gomez, Podladchikova, Veronig, Gomory @  e-mail : jpalacios[at]leibniz-kis.de, J.RodriquezGomez[at]skoltech.ru, T.Podladchikova[at]skoltech.ru, astrid.veronig[at]uni-graz.at, gomory[at]ta3.sk

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
Main Objective: The proposed objective is the estimation of the plasma beta parameter for different magnetic field regimes: (a) for quiet sun and faculae, (b) for coronal holes.

Scientific Justification:
We would like to ask for support to HINODE for the following GREGOR campaign, already scheduled, and IRIS (program approved). We are also submitting the OBS-IDs to IRIS at the time of this submission. The proposal plan is a summary of the proposal submitted to GREGOR, and awarded with 12 days.

The proposed objective is the estimation of the plasma beta parameter for different magnetic field regimes: (a)for Quiet Sun and faculae, (b) for Coronal Holes.

The plasma beta parameter is defined as the ratio of the magnetic pressure over the kinetic pressure. The plasma beta is usually estimated with different models of magnetic field, density and temperature. In this proposal we propose to observe different Sun layers where we can retrieve these magnitudes, namely, the magnetic field, density and temperature through the most direct possible methods from the proposed observing campaign.

The plasma beta parameter is very important for different physical phenomena in the solar atmosphere, such as solar wind and how it is accelerated. In the most dense layers, such as the photosphere, it is also relevant, because small magnetic changes in this layer or local heating can affect the magnetic loops showing higher values in the beta parameter. The chromosphere, transition region and corona are the least explored layers, and the plasma beta is not so well known for these layers.

(a) The structure of the solar atmosphere is complex, due to the interchanging roles of plasma and magnetic pressure. This behaviour is usually described by the plasma beta. Studies about the plasma beta in different layers of the solar atmosphere and their dependence with height is presented in Rodriguez Gomez (2017, 2018). Recently we have extended this study of the plasma beta evolution in the solar corona for different features as Quiet Sun, faculae and Active Regions (i.e, closed magnetic field regime).  

(b) Coronal holes  are an important quiet solar source for space weather events. They are observed as dark coronal structures compared with their surroundings in far ultraviolet or X-ray filters. Since they are characterised by an imbalance in the magnetic flux, the estimation of the plasma beta is very interesting for different reasons: because of the aforementioned magnetic field; due to the very reduced plasma pressure; and more interestingly, as a test bench for flux transport models. Coronal holes are very common in the decay and minimum of the solar cycle. Since they exhibit a more unipolar magnetic carpet than the regular Quiet Sun (QS), the interest lies on relatively low-medium magnetic field, more unipolar (open), as another magnetic regime to estimate the plasma beta parameter.

The main objective of this campaign is to have co-spatial and co-temporal observations which can provide constraints to the values on magnetic field, temperature and density to help us to complete a more detailed depiction of the plasma beta with height, which in turn will be useful for solar wind and many other aspects. This description will use the observations as follows.

HINODE/SP may provide spectropolarimetric data in the photospheric 6301 and 6302 A lines, for two similar heights in the photosphere. This photospheric magnetic field can be extrapolated to compute the magnetic pressure, or used as input for magnetic model, for different heights. The retrieved magnetic field can be used for further forward modelling of the magnetic field or using photospheric magnetic field and extrapolate with PFSS or NLFFF. Another description of temperature can be obtained through magnetic field extrapolations.  

HINODE/XRT is the most adequate instrument to probe coronal layers with imaging, and to infer heights in small loops or other structures. XRT differential emission measures curves can be useful for inferring densities.

HINODE/EIS can complement the chromospheric information obtained by GREGOR, and IRIS observations.  

Other coordinated observations, as with IRIS, will help to complete the picture of the plasma beta diagram
with height.  

Rodriguez Gomez, J.M , 2017, PhD thesis
Rodriguez Gomez. J.M, Vieira ,L., Dal Lago,A., Palacios,J.,  2018, Ap.J., 852,137

 request to SOT
-SOT: SP: SP full Stokes polarimetry,  
-Normal maps 19"x 82" 120x(512x112x1x4) 10 min 68 Mbits
In case of stable conditions at GREGOR:
-Deep maps 19"x 82" 120x(512x112x1x4) 20 min 81 Mbits
-In case of some dynamical event appear on our observation targets, the fast maps can be used:
-Fast maps: 20"x 82" 64x(256x112x1x4) 4 min 19 Mbits

 request to XRT
-XRT: filters: Al-mesh, Al-poly, Al-poly+Ti-poly, and thin-Be  384x384 px, FOV= 394" x 394", every 5 minutes.

 request to EIS
We would like to run EIS HOP 232:

The EIS study is intended to cover a large area in a reasonable time while retaining a number of good diagnostics. Only snapshots of jets will be possible due to the cadence, but previous studies suggest a number of jets should be observed over a period of several hours. The study name is "ISSI_jet_1," and the parameters are:

Duration: 1hr 2min
Slit: 2"
Step size: 3"
Raster size: 180"x336"
Exposure time: 56s
Data volume: 27.8 MBit
Data rate: 7.4 kBit/s
Compression: JPEG92

The study should be repeated to fill the available time slot. For EIS purposes,  the time slot is recommended to be at least 12 hours.  The data volume over 12 hours would be 323 MBit.

 other participating instruments
IRIS: Approved IRIS proposal and modes. These are the following:  

-standard mode for our campaign (15hx 60h), 15s exposure, mode 38:
3620260038  |  Medium sparse 16-step raster 15x60 16s   Deep x 15  FUV spectrally reb  |     261,22    | 78,24    |       0,2     | 16,3+/-0,1 |  261+/-0   | 65,3+/-0,0 | 65,3+/-0,0 | 65,3+/-0,0 | 65,3+/-0,0

-fast large mode (30hx 60h) , 8s exposure, mode 41:
3620258041  |  Medium coarse 16-step raster 30x60 16s   Deep x 8  FUV spectrally rebi  |     148,82    | 78,24    |       0,4     |  9,3+/-0,1 |  149+/-0   | 37,2+/-0,0 | 37,2+/-0,0 | 37,2+/-0,0 | 37,2+/-0,0

-deep large mode (30hx 60h) ,15s exposure, mode 41:
3620260041  |  Medium coarse 16-step raster 30x60 16s   Deep x 15  FUV spectrally reb  |     261,22    | 78,24    |       0,2     | 16,3+/-0,1 |  261+/-0   | 65,3+/-0,0 | 65,3+/-0,0 | 65,3+/-0,0 | 65,3+/-0,0

Dates:  From 2019 Oct 10 to 2019 Oct 22.  Best on consecutive days.

Time window:  Best from 08:00 onwards. (If this is not possible, these times can be set as those for IRIS, which is From Oct 10 to Oct 16, from 11 UT onwards. From Oct 17 to Oct 22, from 10 UT onwards).

Target(s) of interest:  Quiet sun, weak faculae and non-polar coronal holes, at sun center and limb.  

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