Coronal hole plume observation, 24 & 25-Mar-2016

Shortly after the previous observation (19-Mar-2016) there was an equatorial extension of the north coronal hole that passed the central meridian so I requested observations during 24-25 March OP.

24-Mar-2016

I chose a plume that was a little weak and a bit fractured at the time of target selection. However, at the time of the observation there was a nice, well-defined plume close to the target. Unfortunately it was to the right of the pointing, and the EIS sit-and-stare pointing was not great. In fact the small plume to the bottom-left of the nice plume is actually observed (see movie). For IRIS the plume was a little to the right, so the raster only saw about half of the plume, although the SJI saw it all. There's some interesting dynamic events seen in both 171 and 1400. For example a jet at 01:00 that is caught with the spectrometer.

IRIS obtained 62 16-step rasters between 23:15 and 03:49. It looks like 2832 was taken every 4th exposure (the rest being 1400).

The EIS observation was:

23:33-23:36   PRY_slot_context_v3
23:36-05:44   Cool_loop_stare [sit-and-stare, 660 repeats]
05:44-05:48   PRY_slot_context_v3
 

I think the pointing is actually to the right of the one displayed in the movie.

The XRT observation from the CO's notes was:

XOB #1B1E: CH Al/poly+Thin-Be-256x256-1min cad-AEC0-HOP266, with G-band
(3ms/3ms VLS=CLS)
   03/19 12:03:00 - 03/19 18:00:00 : IHOP 266: Coronal hole plume obs.

SOT took SP fast scans of size 123"x160" at the following times: 23:35, 02:00, 03:30 and 05:07 (click on links to access images at LMSAL site). The entry that appeared in the CO's notes was:

2016/03/24 23:35:00 - 2016/03/25 05:51:05
   SOT pointing: (-87,443) tracking
     SP02 (0x019a) Fast map, 123"x160", 1-side CCD ROI=1
     SP02 (0x019a) Fast map, 123"x160", 1-side CCD ROI=1
     SP02 (0x019a) Fast map, 123"x160", 1-side CCD ROI=1
     SP02 (0x019a) Fast map, 123"x160", 1-side CCD ROI=1    

An example LOS magnetogram from 23:35 is given below.

25-Mar-2016

The bright plume from yesterday is still present. Just behind it and to the left there's an anemone-like bright point which seems to have some jetting activity. The base of the plume may be the interesting thing: it seems to have a dark hole in front of it (171) with quite a lot of dynamics. Note that there are a number of small dynamic features just to the left of the plume.

The EIS sit-and-stare catches the little bright point behind the plume, and some of the plume emission. However the plume is very weak. There are a lot of dropouts in raster 3 and 4. Generally this doesn't look to be an interesting data-set.

The IRIS observation as printed in the planner's notes was:

+0 18:49-22:47     HOP266: Small-sclale reconnection in CH plumes [76", 444"]

The EIS observation was:

18:45-18:48   PRY_slot_context_v3
18:48-22:54   Cool_loop_stare [440 repeats]
22:54-22:57   PRY_slot_context_v3
 

Note that both EIS and IRIS ran CH boundary studies after this observation.

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