Summary: Nonthermal Velocities in the Solar Transition Zone
J.G. Doyle, E. O'Shea and R. Erd'elyi
Armagh Observatory, Armagh BT61 9DG, N. Ireland.
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K.P. Dere and D.G. Socker
E. O. Hulburt Center for Space Research, U.S. Naval Research Laboratory,
Washington DC 203755000, USA.
Department of Pure and Applied Physics, The Queen's University of Belfast,
Belfast BT7 1NN, N. Ireland.
(Received ..... ; Accepted in final form .....)
Abstract. Nonthermal velocities are presented for spectral lines covering the tem
perature range 10 4 K -- 10 6 K, measured from high spectral resolution data for several
solar features observed at the limb by the High Resolution Telescope and Spectro
graph (HRTS), including a coronal hole, `quiescent regions' and several small scale
active regions. These results are compared with predictions based on acoustic waves
and heating via Alfv'en waves. It is likely that more than one mechanism is operating