Physics and Astronomy Space Plasma Seminar
Dr. Yuri Y. Shprits, UCLA, Research Geophysicist, Institute of Geophysics and Planetary Physics, Dept of Earth and Space Sciences, and Dept of Atmospheric and Oceanic Sciences
Title: "Ultra-Relativistic Electrons in the Van Allen Radiation Belts"
Abstract: The Van Allen radiation belts consist of energetic electrons and ions
at energies above 100 keV trapped by the Earth's magnetic field. These
very energetic particles may be harmful to satellite electronics and
humans in space. Observations together with predictive and data
assimilative modeling showed that energetic electrons can be
accelerated to relativistic energies by taking energy from ULF and
VLF plasma waves during resonant wave-particles interactions. Recent
observations by NASA's Van Allen Probes showed an event where three
radiation zones were observed at ultra-relativistic energies. The
additional middle, and unusually narrow, belt persisted for
approximately 4 weeks. Detailed observations from the Van Allen Probes
mission and Versatile Electron Radaition Belt (VERB) code modeelling
demonstrate that different physical processes can dominate
acceleration and loss of particles at ultra-relativistic energies,
which explains the unusuall spacial and temporal structures in the
radiation belts.