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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0364

Observing magnetic field by Hinode(SOT/SP) in plume and non-plume regions seen by IRIS and AIA

plan term


@ @


 name : Tiwari, Avallone, DePontieu @  e-mail : tiwari[at]lmsal.com, ellis.avallone3[at]gmail.com, bdp[at]lmsal.com

contact person in HINODE team

 name : Tarbell, Shine @  e-mail : tarbell[at]lmsal.com, shine[at]lmsal.com

 abstract of observational proposal
Main Objective: To detect any mixed-polarity field, unresolved by HMI, at the base of solar plume and non-plume regions observed by IRIS and AIA

Scientific Justification: On-disk solar coronal plumes, best seen in EUV -- AIA 171 A -- form/decay as a result of flux convergence/divergence at their base (Wang et al. 2016; Avallone et al. 2018). It is proposed that flux cancellation, leading to small-scale jets at plume base, is the primary mechanism for plume formation (Raouafi and Stenborg 2014). Avallone et al. (2018) found that plumes are dominantly unipolar in HMI magnetograms, and have similar lifetimes, peak luminosities, base magnetic fluxes in quiet regions and coronal holes. They also found locations of flux convergence forming no plumes in AIA 171, thus suggesting that a critical magnetic field is necessary but not sufficient to form a plume. Moreover, this summer we found hardly any differences between bases of plume and non-plume regions using IRIS MgII and Si IV SJ and spectral data. We propose to repeatedly scan a large FOV of a coronal hole or quiet region by IRIS and SOT/SP, for more than a couple of days, to catch a few plumes, and similarly behaving non-plume areas, and investigate any differences between plume and non-plume regions -- this includes finding out if there is mixed-polarity flux present at plume/non-plume base in SP data.

 request to SOT
Normal scan mode. As many maps per day as possible (2-4).
FOV: 164*123h 768x( 768x112x1x4) 69 min 700 Mbits 4.8s integration; should be able to get 3 maps in about 3.5 hours

It is expected that SP scans cover the same region as requested for IRIS.

 request to XRT

 request to EIS

 other participating instruments
Repeated scans requested.

High telemetry rate:
3620106077 | Very large dense 320-step raster 105.3x175 320s Deep x 4 Spatial x 2 | 1657.36 |2051.85 | 0.8 | 5.2+/-0.1 | 1657+/-0 | 20.7+/-0.0 | 20.7+/-0.0 | 20.7+/-0.0 | 20.7+/-0.0

Low telemetry rate:
3640106077 | Very large dense 320-step raster 105.3x175 320s Deep x 4 Spatial x 2 | 1630.16 |1308.43 | 0.5 | 5.1+/-0.1 | 1630+/-0 | 20.4+/-0.0 | 20.4+/-0.0 | 20.4+/-0.0 | 20.4+/-0.0
Roll angle of the slit: 0


1. Start and end dates: 17-19 October 2018. (3 consecutive days : note that the end time of the last obs is on 20 October)

2. The minimum number of observation days: 3 (so that we have caught a few plume and a few non-plume regions with similar flux convergence at base). Preferable is 4-6 days of consecutive observations.

3. Provide desires and requirements for continuity of observations: "three consecutive days are required," "six consecutive days are desired."

Time window: 14UT - 07UT the next day (17 hours)

Target(s) of interest: quiet Sun - coronal hole, on-disk (within 60 degrees, preferably following from -50 degrees West to 50 degrees East).

Although we prefer coronal holes for plume and non-plume observations, because plumes in quiet regions and coronal holes possess similar characteristics, our purpose would be served even if plume and non-plume regions in quiet regions are scanned.

Coordinate targets and times with IRIS and maintain XRT synoptics.

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