Details

Autor(en) / Beteiligte

• Zarro, Dominic M.
• Canfield, Richard C.
• Metcalf, Thomas R.
• Strong, Keith T.

Titel

Explosive plasma flows in a solar flare

Ist Teil von

• The Astrophysical journal, 1988-01, Vol.324 (1), p.582-589

Ort / Verlag

Legacy CDMS: University of Chicago Press

Erscheinungsjahr

1988

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Solar Maximum Mission soft X-ray data and Sacramento Peak Observatory H-alpha observations are combined in a study of the impulsive phase of a solar flare. A blue asymmetry, indicative of upflows, was observed in the coronal Ca XIX line during the soft X-ray rise phase. A red asymmetry, indicative of downflows, was observed simultaneously in chromospheric H-alpha emitted from bright flare kernels during the period of hard X-ray emission. Combining the velocity data with a measurement of coronal electron density, it is shown that the impulsive phase momentum of upflowing soft X-ray-emitting plasma equalled that of the downflowing H-alpha-emitting plasma to within one order of magnitude. In particular, the momentum of the upflowing plasma was 2 x 10 to the 21st g cm/s while that of the downflowing plasma was 7 x 10 to the 21st g cm/s, with a factor of 2 uncertainty on each value. This equality supports the explosive chromospheric evaporation model of solar flares, in which a sudden pressure increase at the footprint of a coronal loop produces oppositely directed flows in the heated plasma.