Quantifying the spatiotemporal distribution of Ultralow Frequency waves in global simulations

Abstract:

It is well known that relativistic electrons in the outer radiation belt are highly dynamic and respond to impulsive interplanetary structures interacting with Earth’s magnetic field. Two known mechanisms that contribute to the observed dynamics of these electron populations are: Ultralow Frequency (ULF) waves and magnetopause shadowing. The former causes the electrons to change their radial location in order to conserve the quantity associated with the electrons’ azimuthal drift around Earth; the latter describes the process by which these electrons leave Earth’s inner magnetosphere and are lost to interplanetary space. The present work couples the bounce-averaged kinetic Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model to simulate the ring current and radiation belt populations with the Block Adaptive Tree Solar wind Roe-type Upwind Scheme (BATS-R-US) global magnetospheric MHD and ionospheric potential models in order to quantify the radial, azimuthal, and temporal distribution of ULF waves generated by the interaction between impulsive solar wind structures and Earth’s magnetic field. Changes to and losses of relativistic (1-5 MeV) electron populations resulting from the aforementioned mechanisms are investigated.