Creating a new online research log.
Created several new spacetime plots of the full IRIS observation:
The horizontal long-dashed line shows the upper-limit cutoff of the IRIS SJI FOV (i.e. the rightmost side of the leftmost image in the 4-step SJI 1400 Å raster).
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Blob B1
There are several "blobs" of interest during the IRIS observation. I still need to construct a consistent system for identifying/naming the blobs (B1, B2, ...) I will be focused today on the obvious first blob, which I will refer to as B1. B1 is identified in the following spacetime plot:
- Add the correct y-axis to this (this will require calculating the tilted axis based on the pixel shifts).
B1 first appears at ~240 s (first vertical dashed line) and continues to rise until ~460 s (second vertical dashed line), when it is lost as it rises above the solar limb. This gives a total lifetime of ≥220 s. From Brannon et al. (2014), I found that the mean free path in the corona is given by
With a coronal sound speed of , this gives a natural coronal time scale (as a sound transit time) of s. Thus, B1 survives for ~650 t_{cor}, which is... exceedingly long, in my estimation, for a HD blob unconfined in any other way.
No notes today.
Ryan emailed me on Nov 24 with a question about a possibly redundant SJI 2832 flat field from 2014-10-09:
http://solar.physics.montana.edu/sbrannon/iris/calibration_files/sjiflat/20141009_SJI_2832_chaeflat_final.fits
Have responded to say I'll check into this. It seems to have been taken just before a bake-out so maybe was a check on that? There's no record of it in the MSU IRIS calibration Google Sheet...
- Find out if this is redundant or needed in the pipeline. Follow up with Ryan this week.
ZEROTH beam collimator is aligned.
ZEROTH ready for baffles to be installed? Cappy and Suman will be in lab this week.
- Coordinate with C&S to see if there's anything I can do next Sunday.
Perhaps the more relevant time scale for the blob B1 is L/cs, where L is the size of the blob. This is if the blob is not in pressure equilibrium.
Suppose the blob is in pressure equib. Then different times scales will be relevant (thermal conduction, etc.)
To-do for this week:
- Dig into the background subtraction, especially as regards the upper end and the 4-step banding.
- Calculate timescales for blob dissepation, compare with simulation results.
- Touch base with Cappy and Suman for ZEROTH baffling.
- Follow up with Ryan re: redundant flat field.
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End of document.