On the coalescence of twisted flux tubes
作者:
ArnabRai Choudhuri,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 1988)
卷期:
Volume 40,
issue 3-4
页码: 261-291
ISSN:0309-1929
年代: 1988
DOI:10.1080/03091928808208828
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
We study the problem of the coalescence of twisted flux tubes by assuming that the azimuthal field lines reconnect at a current sheet during the coalescence process and everywhere else the magnetic field is frozen in the fluid. We derive relations connecting the topology of the coalesced flux tube with the topologies of the initial flux tubes, and then obtain a structure equation for calculating the field configuration of the coalesced flux tube from the given topology. Some solutions for the two extreme cases of low-β plasma and high-β plasma are discussed. The coalesced flux tube has less twist than the initial flux tube. Magnetic helicity is found to be exactly conserved during the coalescence, but the assumptions in the model put a constraint on the energy dissipation so that we do not get a relaxation to the minimum-energy Taylor state in the low-β case. It is pointed out that the structure equation connecting the topology and the equilibrium configuration is quite general and can be of use in many two-dimensional flux tube problems.
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