Quasi-static evolution of a force-free magnetic field

✍ Scribed by J.J. Aly

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 734 KB
• Volume: 59
• Category: Article
• ISSN: 0010-4655
• DOI: 10.1016/0010-4655(90)90152-q

✦ Synopsis

We consider in the half-space (z >0) a simple-topology force-free magnetic field B embedded in a highly conducting plasma (resistivity a) and its quasi-static evolution driven by motions imposed to the feet of its lines on the boundary {z = 0).

We first study the case when B is an x-invariant arcade, discussing in particular: (i) for a = 0, the existence of stable equilibria corresponding to arbitrarily large shearing, and the qualitative time behaviour of the field (in particular in the limit -~oo); (ii) for a # 0, the possibility of a fast transition by reconnection from an arcade to a complex topology configuration having a lower energy, but the same "distribution of magnetic fluxes". We thus consider a fully three-dimensional field (having an "arcade" or a "tube" topology), showing in particular how it is possible to extend to that situation some of the results obtained for an x-invariant arcade when a =0.