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: http://star.arm.ac.uk/~ambn/abstract282.html
Дата изменения: Wed Apr 29 13:16:33 1998 Дата индексирования: Tue Oct 2 00:24:13 2012 Кодировка: Поисковые слова: coronal hole |
L. Teriaca, D. Banerjee and J. G. Doyle
Armagh Observatory, Armagh, BT61 9DG, N. Ireland
We study the variation of the line width and electron density as
a function of height above the north polar coronal hole from forbidden
spectral lines of Si VIII. The spectra were obtained with the Solar Ultraviolet
Measurement of Emitted Radiation spectrometer flown on the Solar and Heliospheric
Observatory spacecraft.The present data show that the non-thermal velocity
increases from
at 27 arcsec above the limb to
some 250 arcsec (
180,000
km) above the limb. The electron density shows a decrease from
to
over the
same distance. This data implies that the non-thermal velocity is inversely
proportional to the quadratic root of the electron density, in excellent
agreement with that predicted for undamped radially propagating Alfvén
waves. We show that the energy flux associated with these hydromagnetic
waves is sufficient to drive the high velocity solar wind streams.