Current sheets formed by Alfvén and magnetosonic pulses in the vicinity of the null line of the magnetic field

Abstract

A study is made of the propagation of an Alfven pulse and the superposition of an Alfven and a magnetosonic pulse in the vicinity of the magnetic null line (the X point). It is shown that, on long time scales, the poloidal components of the velocity and magnetic field relax to steady-state distributions similar to those in the case of a magnetosonic pulse. In the essentially nonlinear problem under investigation, the steady-state distributions of the toroidal components of the velocity and magnetic field are found to be close to those in the corresponding linear problem. It is established that two-dimensional effects play an important role in the evolution of the forming current sheets.