Fast electron slowing-down and diffusion in a high temperature coronal X-ray source |
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Ross Galloway Submitted: 2005-05-10 10:39
Finite thermal velocity modifications to electron slowing-down rates
may be important for the deduction of solar flare total electron energy.
Here we treat both
slowing-down and velocity diffusion of electrons in the corona at flare
temperatures, for the case of a simple, spatially homogeneous source.
Including velocity diffusion yields a consistent treatment of both
`accelerated' and `thermal' electrons. It also emphasises that one may
not invoke finite thermal velocity target effects on electron lifetimes without
simultaneously treating the contribution to the observed X-ray spectrum
from thermal electrons. We present model calculations of the X-ray
spectra resulting from injection of a power-law energy distribution of
electrons into a source with finite temperature. Reducing the
power-law distribution low-energy cutoff to
lower and lower energies only increases the relative magnitude
of the thermal component of the spectrum, because the lowest energy
electrons simply join the background thermal distribution. Acceptable
fits to RHESSI flare data are obtained using this model. These also
demonstrate, however, that observed spectra may in consequence be
acceptably consistent with rather a wide range of injected electron
parameters.
Authors: R. K. Galloway, A. L. MacKinnon, E. P. Kontar, and P. Helander
Projects: RHESSI
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Publication Status: A&A (in press)
Last Modified: 2005-05-10 10:39
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