๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

A model of solar flares and faculae

โœ Scribed by J. H. Piddington


Publisher
Springer
Year
1973
Tongue
English
Weight
767 KB
Volume
31
Category
Article
ISSN
0038-0938

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โœฆ Synopsis


Theories of solar flares based on the storage of energy (usually as magnetic energy) in the solar atmosphere are shown to be incompatible with observational data.

The sunspot energy deficit and the photospheric faculae both involve energy fluxes comparable with the flare requirement ( ~ 3 โ€ข 1029 erg s-~). Both also require a subsurface system of waves or oscillations, perhaps those discussed by Danielson and Savage and by Wilson. The flare model proposed is based on a temporary diversion of this energy carried by Alfv6n waves through spots and magnetic elements or micro-pores; the calculated plasma perturbation velocity in the umbra is about 6 km s -t for a major flare.

In the atmosphere the wave energy divides into two parts to produce the cool, stationary optical flare and the particle flare. The first part is dissipated around flux tubes which are mainly horizontal in the chromosphere and which tend to concentrate along the magnetic neutral line (B ~ = 0). Each tube vibrates individually as a taut wire in a viscous fluid, to excite the fluid just outside the tube. The second part of the energy emerges along tubes mainly vertical in the chromosphere and is converted to shock waves in the corona and then to particle energy for the radio and X-ray flare and the blast wave.

The model includes white-light faculae, quasi-permanent X-ray and fast-particle emissions, sympathetic flares and surges. An unambiguous test would be provided by observations of plasma motions of a few kilometres per second in spots and micro-pores.


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