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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0359

Center-to-limb observations of the quiet Sun with ALMA

plan term

@ @


 name : Nindos @  e-mail : anindos[at]uoi.gr

contact person in HINODE team

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

 abstract of observational proposal
Main Objective:
ALMA-Hinode-IRIS coordinated observations of several quiet Sun regions to study the center-tolimb variation.

Scientific Justification:
We intend to carry out center-to-limb observations of the quiet Sun with ALMA at two frequencies (100 and 230 GHz) and perform detailed tests of 3D models of the quiet chromosphere. These observations will shed light on the thermal structure of the quiet chromosphere by comparing them with state-of-the-art radiative MHD simulations and simultaneous imaging and spectral observations from IRIS and Hinode. Several spectral lines observed by IRIS are formed at about the same height as the mm continua observed with ALMA, but probe different plasma properties. Hinode SOT and XRT data will provide context information about the photosphere and corona, respectively. We will assess whether the models can reproduce the observations and in case of discrepancies we will investigate their origin and how the models could be adjusted. The comparison of observations and models will also help us clarify the role of spicules in the limb brightening.

 request to SOT
Regular fast maps: 3.8 s for one position (2 cycles, 1.6 s). The maps should be 45''-wide, therefore for 150 positions (0.3'' x 150 = 45'') 9.5 minutes will be required for each map. Along each ALMA position angle, we request SOT observations at six discrete regions (their coordinates will be supplied to the planners a few days before observations).

 request to XRT
A few full-sun images just before and just after the ALMA observations. We request the Al-poly and Al-mesh to be used with a 2x2 binning, giving a spatial resolution of ~2"/pixel.

 request to EIS

 other participating instruments
IRIS Requests: Bart De Pontieu recommends:
3640338042 | Large coarse 16-step raster 30x120 16s Deep x 8 Spatial x 2,
Spectra | 146.40 | 62.21 | 0.3 | 9.2+/-0.1 | 146+/-0 | 36.6+/-0.0 | 36.6+/-0.0 |36.6+/-0.0 | 36.6+/-0.0
We request the execution of the above program at nine discrete pointings along each ALMA position angle (their coordinates will be supplied to the planners a few days before observations). Bart de Pontieu has informed us that between June 15 and 30, IRIS will not be able to roll beyond -70 and +50 degrees. He also noted that after June 15, IRIS observations along the ALMA East-West position angle will not be possible. These limitations will be taken into account for thecomputation of the IRIS pointings.


Dates: The ALMA observations will take place in June or July 2018
Time window: We have asked for one 4-hour session of ALMA observations. We request synoptics to be shifted before or after our observations. We also request IRIS to not be in eclipse during our observations.

Target(s) of interest: At each ALMA frequency we will scan six position angles, each one from disk center to the limb with a step of 30 degrees between successive position angles (i.e. each ALMA mosaic will have a length of about the solar radius and a width of about 120").

Previous HOP information:
333 (March 2017)
353 (April 2018)

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