RHESSI Tohban report, 16-Aug-2004 to 23-Aug-2004
Hugh Hudson, hhudson@ssl.berkeley.edu


1. Solar Activity

Happy days were here again:

How many GOES flares occurred?
  Flares above B, C, M, X class were      5    46    13     1
And how many of these are listed in the RHESSI flare list?
  Flares above B, C, M, X class were      1    34    11     1
And how many had EXCELLENT coverage?
  Flares above B, C, M, X class were      1    18     6     0
       
There were RHESSI flares/GOES flares         150 /           65
over the time range 15-Aug-04 22-Aug-04

This activity was the result of NOAA region 656, which crossed
the W limb on August 19. There was an X1.8 event on Aug. 18, just
on this side apparently. There was a steady succession of soft
X-ray brightenings at the SW limb from the region on the far side,
with occultation heights as large as 70,000 km. However there
was virtually no coronal activity, as inferred from the lack of
metric radio phenomena (except for type III) and from the lack
of CMEs (except for a big bright one associated with the X-class
flare). Still this region provides somebody with an opportunity
to study the hard X-ray corona, at least in the context of type
III bursts.

2. Memory Management

The thin shutter was locked in place (1-3 mode) initially, and
then returned to autonomous state 2004-231-17:51:04. This was 
to combat the huge memory loads from the new trapped particles
and from solar X-rays. The X-class flare was observed in 
autonomous mode.

With the region gone the memory loads became less critical, so
decimation was returned to "active_vigorous" 2004-236-16:05:14 UT.

The data from this period are extremely interesting housekeeping-wise
since we exercised the decimation levels pretty completely. It is hard
to keep track of the behavior of the instrument - one needs to look
at Jim's monitor plots, uncorrected, while at the same time viewing
pages accessible from

http://sprg.ssl.berkeley.edu/~tohban/decimation_guide.html

and running the command line to get actual numbers from OBS_SUM_RATE
and OBS_SUMM_FLAG objects. I didn't finish this task but in principle
we need to check on whether we are doing this right, and what effect
the decimation has on data analysis. I (HSH) plan to return to this
on my next tohban occasion unless somebody beats me to this task.

4. Data Gaps

An unexplained gap at 17-Aug 14:15-16:15 (thanks to Peter for noticing).

5. Discoveries

* It's easy to see the G8 telemetry noise (only at the lowest energies)
during utter quiet conditions, by reference to Sa"m's RHESSI-WIND
plot pages. See 2004 Jul 01 15:40 for a nice clear example.

* The orbit now is exactly aligned with the clock, ie terminators agree
from day to day within a second.