Effect of the radial boundary condition on Alfvén wave dynamics in reduced magnetohydrodynamics

The effects of different boundary conditions on Alfvén wave dynamics in reduced magnetohydrodynamics are described. If one assumes that the derivative or the second derivative of the electrostatic potential is zero at one of the radial across the magnetic field boundaries, radially localized guided Alfvén wave solutions are possible, but if is set to zero grounded at both boundaries, the solutions consistent with the boundary condition exhibit radial propagation of energy. To confirm the ideas discussed, numerical tests were done in slab geometry with a density gradient across the magnetic field. © 2008 American Institute of Physics. DOI: 10.1063/1.2898409