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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0266

Small-scale reconnection in coronal hole plumes

plan term


@ @


 name : Young, Raouafi @  e-mail : NourEddine.Raouafi[at]jhuapl.edu

contact person in HINODE team

 name : Young @  e-mail : pyoung9[at]gmu.edu

 abstract of observational proposal
Raouafi & Stenborg (2014, ApJ, 787, 118) recently found that coronal hole plumes demonstrate a large number of small jets (termed jetlets) and transient bright points that are due to the quasi-random cancellation of magnetic fragments at the plume footpoints, and suggested that these are the main energy source for plumes.

In this IHOP we will extend this analysis using the high spatial resolution of SOT to resolve the small-scale magnetic field at the plume bases, and use IRIS to search for evidence of reconnection through Doppler shifts and broadening of transition region and chromosphere lines. In addition, coronal emission lines of EIS will be used to search for transient brightenings and line broadening in the corona that result from the energy release.

A plume should be identified in either a low-latitude extension to a coronal hole, or an equatorial coronal hole. The combined 171-193-211 images available at http://sdowww.lmsal.com/suntoday are recommended for identifying plumes in coronal holes as they show up as blue features within dark coronal holes.

A duration of 4 hours is requested in order to monitor the evolution of the plume.

 request to SOT
Na I magnetograms and Ca II at full spatial resolution and 1-2 minute cadence. Occasional G-band image. Field-of-view at least 40" x 40".

 request to XRT
Use a low temperature filter (e.g., Al-poly) and a hotter filter (e.g., Be-thin). Field of view should be 256x256 and the full spatial resolution should be used. Cadence should be 1 minute or better in each filter. The expected structures will be faint, so long exposures are needed.

 request to EIS
A sit-and-stare study is used. The slit should be placed through the footpoint of the plume and along the axis of the plume.

Repeat the study Cool_loop_stare to fill the available time slot.

Begin and end the sequence with a single run of PRY_slot_context_v3 (ID 353).

 other participating instruments
Request to IRIS
OBSID: 3823009186 - large, sparse 16-step raster (15x120, 16
steps) with 8 second exposure times. Medium linelist.

C II, Mg II h/k and Si IV slitjaw images.

The center of the IRIS raster should be on the base of the plume.


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