Coronal hole plume observation, 21-Apr-2016
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.
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.