The Comprehensive Inner Magnetosphere‐Ionosphere Model

Abstract

Simulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric density, Region 2 currents, convection potential, and precipitation in the ionosphere. It incorporates whistler mode chorus and hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. CIMI thus represents a comprehensive model that considers the effects of the ring current and plasmasphere on the radiation belts. We have performed a CIMI simulation for the storm on 5-9 April 2010 and then compared our results with data from the Two Wide-angle Imaging Neutral-atom Spectrometers and Akebono satellites. We identify the dominant energization and loss processes for the ring current and radiation belts. We find that the interactions with the whistler mode chorus waves are the main cause of the flux increase of MeV electrons during the recovery phase of this particular storm. When a self-consistent electric field from the CRCM is used, the enhancement of MeV electrons is higher than when an empirical convection model is applied. We also demonstrate how CIMI can be a powerful tool for analyzing and interpreting data from the new Van Allen Probes mission.

Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

“…A ring current model can be considered as a bounce-averaged kinetic code and normally operates with a large number (from hundreds to thousands) of "species", i.e., distributed in energy, pitch angle, or first and second adiabatic invariants. Currently, there are several major ring current models used by the community: the standard Rice Convection Model (RCM) (Harel et al, 1981;Toffoletto et al, 2003) or the RCM-E, a version that includes frictional dissipation (Lemon et al, 2003;Chen et al, 2015); the Magnetospheric Specification Model (MSM) (Wang et al, 2003(Wang et al, , 2004; the Comprehensive Ring Current Model (CRCM) (Fok et al, 1993(Fok et al, , 1995(Fok et al, , 2001(Fok et al, , 2014 and its successor, the Comprehensive Inner Magnetosphere-Ionosphere model (CIMI) (Fok et al, 2014); the Ring current-Atmosphere interactions Model (RAM) (Jordanova et al, 1994(Jordanova et al, , 2001 and its extended version with magnetic equilibrium solver Zaharia, 2008); the Hot Electron and Ion Drift Integrator (HEIDI) code (Liemohn et al, 1999); and the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM) (Ganushkina et al, 2012).…”

Global images of trapped ring current ions during main phase of 17 March 2015 geomagnetic storm as observed by TWINS

“…This point is illustrated in Figures a and b, which show Hamiltonian contours (drift paths) for particles with constant first and second adiabatic invariants, i.e., μ and K , calculated from CIMI [ Fok et al ., ] in the Tsy05 model magnetic field during the main phase of the 17 March 2015 storm. The solid lines in both plots are the drift paths for particles with constant first adiabatic invariant, i.e., μ .…”

Space Weather Effects Produced by the Ring Current Particles

“…A variation of the FRC model is the Comprehensive Inner-Magnetosphere Ionosphere (CIMI) model which also calculates the temporal and spatial variation of the phase space density of electrons in the energy range of 1-4000 keV (Fok et al 2011(Fok et al , 2014. Instead of MHD-related inputs, this model has different inputs based on empirical models.…”