Solar-Terrestrial Wave Connection: Solar/Planetary Whistler-excited Relativistic Electron Processes and Coronal Source as Seed for Magnetospheric ULF Energization.

Abstract:

The formation mechanisms of relativistic electrons in space due to electromagnetic waves are crucial to discern the most relevant observations, since most of the emissions in the Universe are due to energetic electrons. Direct observations of the ULF/VLF waves, together with magnetospheric and solar energetic populations indicate clearly that generation of intense fluxes of relativistic electrons occurs during the evolution of active magnetized plasma systems. Examples of relativistic electron energization include the (a) recovery phase of a planetary magnetic storm, (b) post solar coronal mass ejection activity and (c) various astrophysical electromagnetic bursts. It is suggested that there exists a universal mechanism, which may explain electron energization at the vastly different magnetized plasma environments. The favorite configuration consists of an inhomogeneous, marginally stable magnetic field anchored at a given large scale structure (1) with a local-field excitation of whistler waves due to external magnetic reconfiguration or (2) adiabatic cross-field diffusion due to global eigen-oscillations. The relevant magnetic reconfigurations include planetary magnetic storm and solar CME, respectively. An additional prospect of coupling between solar and terrestrial (planetary) processes may emerge when the solar, whistler-accelerated electrons reach the planetary magnetosphere, serving as a pre-accelerated seed population for the ULF process. The validity for the processes in the experimental contex will be scrutinized. Recent observations may pinpoint to the missing link for the whistler pre-accelerated mechanism.