A model for the generation of magnetohydrodynamic waves by high-altitude nuclear bursts

Abstract

A model for the debris motion promptly following a high-altitude nuclear detonation is taken to be a perfectly conducting sphere expanding at constant velocity into a magnetoplasma, pushing the magnetic field aside, and then abruptly stopping. Representing the electromagnetic properties of the magnetoplasma by a dielectric sensor, Maxwell's equations can be written as two coupled equations for the isotropic and anisotropic modes of propagation. Using a perturbation expansion, these equations can be solved for the two modes as a function of the debris expansion velocity, which can in turn be related to the yield-to-mass ratio of the bomb. The analyses permit evaluation of the amplitude, the spatial and temporal dependence, and the frequency content of the hydromagnetic signal generated by the explosion. The model also yields a physical interpretation of that portion of the hydromagnetic yield that does not appear as radiation and allows evaluation of the efficiency of the system as a radiator of hydromagnetic waves.