Helicity redistribution during relaxation of astrophysical plasmas
We present the first 3D numerical MHD simulations that show that Taylor's relaxation conjecture is not satisfied in some MHD evolution of magnetic configurations encountered in solar physics. We show that magnetic helicity can be slowly injected through the boundary into a magnetic configuration which then evolves into a MHD disruption, with the formation in finite time of a current sheet through which reconnection occurs, leading to a release of magnetic energy. While helicity is well conserved during the process, it is shown that the relaxed state is far from the constant- alpha linear force-free field that would be predicted by Taylor's conjecture.
Amari
T
CNRS, URA2052, CEA-Saclay, F91191 Gif-sur-Yvette Cedex, France.
Luciani
JF