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Perhaps you could help us by asking your colleague for help. Ask him if
the H-alpha light he's observing in is within the Fraunhofer absorption
linewidth. I'm betting it is.
Leigh
That is an old project. We are now doing a Solar Activity project and atpotentials
Kitt Peak we are measuring wavlength shifts of closely spaced lines with
very different excitation potentials or very different ionization
using the 1 meter Fourier Transform Spectrometer. The line are usuallyshapes
separated by 0.1 to 0.001 nanometers. We are doing this over a range of
both excitation and ionization potentials (although the latter are not as
numerous as the former). Then we apply a theoretical model of so called
contribution functions to calculate the shape and details of the line
with depth. This presumably will provide us with more structural detail asspeed
a function of depth in both the photosphere as well as the chromosphere.
We have already observed one thing we sort of expected. Namely, the
chromosphere in particular (having radiative temperatures in the range
of about 15000 to 100000 Kelvins is highly non uniform. This simply means
that applying a simple height vs. depth model is at best highly wishful
thinking. The tops of these layers are the so-called transition region
wherein over a small change in height the temperatues measured in a variety
of ways spikes from the values above to coronal values in the millions and
near condensations hundreds of millions.
By the way one our main conclusions via our rotation project was that the
Sun changes its rotation characteristics rapidly; e.g., the equatorial
can change by 5% in one day! The polar swirls or solar polar vortex seemsthat
to come and go randomly? The appears also to be a secular slow change in
rotation vs. latitude that appears to be modulated by the solar cycle or
the other way around? The rapid changes cite above are probably caused by
very thin "rivers", "streams" and "currents". I find it hard to believe
the Sun changes it angular momentum so rapidly. These ideas have been in a
general way confirmed by Helioseismolgy meaurements.
Jim
Dr. James C. LoPresto
Observtory
Edinboro University of PA
Edinboro, PA 16444
Phone: 814-732-2469