The Pc1 geomagnetic pulsations in light of the Cepheid theory

TL;DR

This paper offers a novel interpretation of Pc1 geomagnetic pulsations, proposing they originate from a pulsed ion-cyclotron wave generator in the outer radiation belt, inspired by Cepheid variable star opacity mechanisms.

Contribution

It introduces a new model linking geomagnetic pearls to a Cepheid-like opacity mechanism involving a pulsed ion-cyclotron wave generator in the radiation belt.

Findings

Proposes a Cepheid-like opacity layer in the Earth's magnetosphere.

Suggests pearls are generated by a Q-modulated ion cyclotron resonator.

Draws an analogy between pearl formation and Cepheid star pulsations.

Abstract

It has been 90 years since the discovery of geomagnetic pulsations in the Pc1 range (0.2-5 Hz), widely known as pearls. In the second half of the last century, the concept of pearls as multiple echoes of a wave packet that propagates along the lines of the geomagnetic field, periodically reflecting off the ionosphere at magnetically conjugate points emerged. This paper proposes an alternative interpretation of the pearls. It is assumed that high above the Earth in the narrow equatorial zone of the outer radiation belt there is a pulsed generator of ion-cyclotron waves. The generator excites a discrete sequence of wave packets, which are recorded in the magnetosphere and on the Earth's surface as a series of pearls. The generator is a Q-modulated ion cyclotron resonator with active filling. The presence of opacity domains adjacent to the resonator's end faces is reminiscent of the opacity layer in the atmosphere of a Cepheid. This association was strengthened by the fact that in both cases the formation of opaque layers is associated with the presence in the medium of ions with different charge-to-mass ratios. Based on this association, the idea of a ponderomotive valve arose, periodically changing the width of the opacity domains, thereby forming a periodic sequence of pearls. The ponderomotive valve in pearl theory is analogous to the Eddington valve in Cepheid theory.