Variational approach for static mirror structures
Abstract
Anisotropic static plasma equilibria where the parallel and perpendicular pressures are only functions of the amplitude of the local magnetic field are shown to be amenable to a variational principle with a free energy density given by the parallel tension. This approach is used to demonstrate that twodimensional smallamplitude static magnetic holes constructed from a GradShafranov type equation slightly below the (subcritical) mirror instability threshold identify with lump solitons of KPII equation, but turn out to be unstable. Differently, largeamplitude magnetic structures, which are stable as they realize a minimum of the free energy, are computed using a gradient method within twodimensional numerical simulations where the regularizing effect of finite Larmor radius corrections is retained. Interestingly, these structures transform from stripes to bubbles when the angle of the magnetic field with the coordinate plane is increased.
 Publication:

Physics of Plasmas
 Pub Date:
 April 2015
 DOI:
 10.1063/1.4919027
 Bibcode:
 2015PhPl...22d2114K