Parallel electric field of a mirror kinetic Alfven wave

It has been shown that an Alfven wave can create an electric field along the magnetic field line due to mirror effect. In a converging magnetic field, mobility of electrons is restricted by the mirror force and a parallel electric field must exist to carry a field aligned current associated with Alfven waves. The parallel electric field created by this mechanism can be much larger than that of a kinetic or inertial Alfven wave when the wave frequency is low enough. The essential mechanism of parallel electric field generation is reduced to the static mirror model in the limit where the wave frequency vanishes.