The SUMER Investigation
The Solar Atmosphere
In the outer solar atmosphere, the plasma temperature, density, flow
characteristics and wave activity vary strongly as a function of height and
of horizontal position. Complex features, such as active regions, prominences,
magnetic loops, bright points, and explosive and turbulent events, will
influence the actual structure of the atmosphere. Generally, the temperature
rises abruptly from values of about 10 000 K in the chromospheric layer,
which occupies the first 2 000 km above the photosphere, to values in excess
of 1 000 000 K in the corona, across a transition region only a few hundred
kilometers thick. The existence of a hot corona requires a persistent
non-radiative energy input to compensate for radiative and conductive losses
and for the solar wind expansion.
The Investigation
The experiment "Solar Ultraviolet Measurements of Emitted Radiation" is
designed for the investigation of
- plasma flow characteristics, turbulence and wave motions;
- plasma densities and temperatures;
- structures and events associated with solar magnetic activity in the
chromosphere, the transition zone and the corona.
Specifically, SUMER will
- measure profiles and intensities of extreme ultraviolet (EUV) lines emitted
in the solar atmosphere ranging from the upper chromosphere to the lower
corona;
- determine line broadenings, spectral positions and Doppler shifts with high
precision and accuracy;
- provide stigmatic images of selected areas of the Sun in the EUV with high
spatial, temporal and spectral resolution and
- obtain full images of the Sun and the inner corona in selectable EUV lines,
corresponding to a temperature range from 10 000 to 2 000 000 K.
Parts of the information gathered with the SUMER instrument are available in our
Pictures section; a list of
Publications is also available here.
A collection of scientific sequences already planned for SUMER can be studied
in the related section of the Operations Guide:
"Predefined Operational Programs".
(Informal) Call for Participation
Scientists interested in this field of study are invited to participate in
the SUMER experiment. For a guest investigator questionnaire, a scientific
sequence form sheet, or for simulation software
on scientific sequences, please contact our Principal Investigator:
Klaus Wilhelm, wilhelm@linmpi.mpg.de
or KWilhelm@solar.stanford.edu
IED, 20 Oct 1995
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