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V. Dynamics of the Chromosphere and Transition Region

Published online by Cambridge University Press:  25 April 2016

R. Grant Athay

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One of the more interesting aspects of the chromosphere-corona transition region is its tendency to exhibit large Doppler shifts. Both the non-thermal velocity component of line widths and the velocity displacement of line positions tend to maximize at temperatures near 105 K. The increase in velocity amplitudes with increasing temperatures below 105 K is readily understood in terms of the increasing sound speed and decreasing densities associated with the outwardly increasing temperature. Why the observed velocity amplitudes should decrease at still higher temperatures is not at all clear, however, and it seems very likely that this phenomenon is indicative of fundamental differences in the dynamics of the upper transition region and corona from those in the lower transition region and chromosphere.

Type
Research Article
Information
Transactions of the International Astronomical Union , Volume 19 , Issue 1 , 1985 , pp. 108 - 110
Copyright
Copyright © Reidel 1985

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