Tearing modes at the magnetopause

Abstract

It is shown that the shear flow present in the magnetopause current layer can destabilize the tearing modes depending upon the Mach number profiles. Using a variational principle, an heuristic stability criterion based on the form of the Mach number profile is obtained. This criterion could be used as a handy tool to search for tearing mode instability of a given magnetopause equilibrium with shear flow. The Doppler shifted magnetic structures produced by the tearing modes would be observable at ultralow frequencies in the range of ∼ 5 – 650 mHz in the satellite frame of reference.