Electron Acceleration By Large-Amplitude Oblique Whistler Waves

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An outstanding problem in magnetospheric physics involves understanding the source and loss mechanisms of the Earth's radiation belt electrons. It is thought that various plasma waves play an essential role in this regard. A recent observation suggests that there may be large-amplitude whistler waves propagating obliquely with respect to the ambient magnetic field. These waves may play a significant role in accelerating the radiation belt electrons to relativistic energies within a few seconds time scale. This project will rigorously study the propagation of large-amplitude whistler waves in an inhomogeneous magnetic field and plasma density by solving the fully nonlinear cold electron fluid equation coupled with relativistic test particle simulation code. Previous work in this area has been limited to the quasi-linear regime, uniform magnetic field and density and parallel propagation of the whistler waves. A wide variety of physics based models are being developed to forecast radaition belt variations for space weather applications. It is important to know whether or not obliquely propagating waves are an important source of particle acceleration. It is similary important to know to what extent a fully nonlinear treatment of the problem is required. In addition to the societal benefits of this research because of its relevance to space weather forecasting, the project has educational benefits as well because a postdoctoral researcher will participate in the research.