Coronal hole plume observation, 21-Apr-2016

There was a small coronal hole close to disk center on 21-April  with quite a large, bright plume in the center. I requested a run of IHOP266 with IRIS and Hinode. The movie below shows AIA 171 images, with the EIS slit indicated. Note that this plume is much weaker (factor 10) than the 19-Mar-2016 plume.

AIA 171 movie at 5 minute cadence. Logarithmic intensity scaling.

EIS data-set

The EIS observation began at 13:06 with PRY_slot_contextLITE, and then four repeats of Cool_loop_stare (approx 4 hours), with a final PRY_slot_contextLITE. The Cool_loop_stare times are: 13:10, 14:07, 15:04 and 16:02 UT.

The data show brief "twilight" periods in the 2nd and 4th files.

Co-alignment with AIA is made easy by a bright point at Y=-117, just to the north of the plume.

Some repeating jets are seen in the Fe XII 195 sequence, especially in the 2nd file. The image below shows a screen-grab from eis_raster_browser for the 2nd file. Time (minutes) is on the X-axis and solar-Y on the Y-axis. The intensity dip at T=40 is due to absorption by the Earth's atmosphere (twilight). Repeating jets can be seen in Fe XII, but not Fe IX.

EIS Fe XII 195 (left) and Fe IX 197 (right) images.

IRIS data-set

The IRIS observation was:

+0 13:14-18:19     HOP 266 small-scale reconnection in coronal hole plumes, target=CH [8", -165"]

69 rasters were performed.

SOT data-set

The planned observation (SOT CO was Masahito Kubo) was:

HOP266 (coronal hole plumes)
  2016/04/21 13:04:00 - 2016/04/21 18:18:05
  SOT pointing: (12,-164) tracking
    SP07 (0x01a0) Fast map, Q65, 123"x123", 1-side CCD, No Summing ROI-1

which looks to be a single raster obtained between 13:04 and 13:25 (approx). The data can be obtained from the SP archive at LMSAL. The longitudinal magnetogram is reproduced below.

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