Generation of sheet currents by high frequency fast MHD waves

• Regular solutions of quasilinear hyperbolic systems may evolve into shocks.
• The shock location is found for high frequency fast MHD waves.
• The result is applied to static axisymmetric equilibria.
• The previous process may lead to the formation of sheet currents and destruction of the equilibrium.

The evolution of fast magnetosonic waves of high frequency propagating into an axisymmetric equilibrium plasma is studied. By using the methods of weakly nonlinear geometrical optics, it is shown that the perturbation travels in the equatorial plane while satisfying a transport equation which enables us to predict the time and location of formation of shock waves. For plasmas of large magnetic Prandtl number, this would result into the creation of sheet currents which may give rise to magnetic reconnection and destruction of the original equilibrium.