A Mechanism for Magnetic Enhancement of Sound-Wave Generation and the Dynamical Origin of Spicules.

Abstract

It is pointed out that a vertical magnetic field through an atmosphere with a small scale height greatly tahances the generation of sound (fast-mode) waves in the fluid motions in the atmosphere. The fluid motions become a monopole, rather than the usual quadrupole, source of radiation. The sound waves ropagate principally in the upward direction along the field. It is suggested that this mechanism, apart from its other applications, operates in the plage areas on the Sun and is responsible for the spicules.