ISSN:
1573-093X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract In this paper we introduce a new parameter, the shear angle of vector magnetic fields, Δψ, to describe the non-potentiality of magnetic fields in active regions, which is defined as the angle between the observed vector magnetic field and its corresponding current-free field. In the case of highly inclined field configurations, this angle is approximately equal to the ‘angular shear’, Δφ, defined by Hagyardet al. (1984). The angular shear, Δφ, can be considered as the projection of the shear angle, Δψ, on the photosphere. For the active region studied, the shear angle, Δψ, seems to have a better and neater correspondence with flare activity than does Δφ. The shear angle, Δψ, gives a clearer explanation of the non-potentiality of magnetic fields. It is a better measure of the deviation of the observed magnetic field from a potential field, and is directly related to the magnetic free energy stored in non-potential fields.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00675538
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