Last Update: 07-DEC-98

Dear colleagues,

please find attached a proposal for a JOP in support of the Lyman-Project
by Petr Heinzel and myself. The proposal is in TEX format.
The idea is to make a SOHO internal test run during the MEDOC campaign in
January 99, and to run the full JOP in the middle of the year, when the
canary island observatories are operational. I volunteer to take the SUMER
part. Please reply, if you have comments or questions.

With best regards,

Werner Curdt

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PROPOSAL FOR A JOINT SOHO-GBO CAMPAIGN TO STUDY CHROMOSPHERIC
AND TR OSCILLATIONS

P. Heinzel and W. Curdt


Scientific objectives:
Based on previous studies which show various oscillations in different lines
observed by SUMER, and given some preliminary indications of how these
oscillations are related to those derived from optical lines
(e.g., a correlation between CaII and Lyman lines), we propose to organize
a joint SOHO-GBO observing campaign which would cover, for the first time,
both optical and UV lines simultaneously. The idea is to run SUMER programmes
devoted to oscillations, like the 'Lyman Programme' of Curdt and Heinzel
(and others, for other UV lines) in the quiet-Sun area (mostly at the disk
centre) and using the solar-rotation compensation. Simultaneously, large GBO
telescopes will observe the same area in optical lines, such as  CaII H or K,
HI H$\alpha$ etc.. MDI as well as optical magnetograms would be also very
useful for understanding the magnetic topology of the area studied (e.g.,
using the extrapolations). For example, recent results of the study of
Lyman-lines oscillations show clearly that power-spectra peaks in L_5 line
concide quite well with those derived from high-resolution CaII data. However,
this is based on the statistical approach and our interest is to see a direct
correlation for individual spatially-resolved features (cell grains, network
structures etc.). This is also very important for future modelling.


Instruments involved:
SOHO-SUMER, oscillation programmes  (Lyman programme, others are welcome; we
plan to use 8 windows covering the higher Lyman lines plus the Lyman continuum
- this, with a 30 sec exposure time, will allow us to obtain a longer time
series, up to several hours). SUMER context images in selected chromospheric
lines will be taken before the time sequence, for coalignment with GBO data. 
SOHO-MDI, hi-res mode in the quiet area around the disk center - JOP with
SUMER
TRACE, context images and possibly a time series (e.g., in Lyman-alpha)
VTT (Tenerife), filtrograms in CaII K2v or Halpha (G\"ottingen- F. Kneer,
Freiburg-M. von Uexk\"ull, and others)
Gregory telescope (Tenerife), hi-res magnetograms (Potsdam-J. Satude,
G\"ottingen)
  

Time-schedule:
We suggest to test SUMER oscillation programmes and their new variants,
together with MDI, during January 1999 MEDOC campaign. For this we will
require some slots of several hours (3-5), preferentially when a quiet region
can be observed near the disk centre. This will be a SOHO internal test-run
without GBO's.
During February, GBO (Tenerife) will establish the observing schedule for 1999.
If a time is allocated to this programme, we will try to organize a campaign
around that schedule.
According to GBO observing time allocation, we may try to organize either a
'minicampaign' for, say, a week (SUMER, MDI, TRACE), or to try to fit in one
of larger SOHO-SUMER campaigns planned for 1999.