Theory, modeling, and integrated studies in the Arase (ERG) project

K Seki ,Shigeto Watanabe,Akimasa Yoshikawa,Tomoaki Hori,Yoshiharu Omura,Naoko Takahashi,Takashi Tanaka,M Nosé ,A Ieda ,Takanobu Amano,Yusuke Ebihara,S Nakano ,M.‐C Fok ,K Keika ,Yutai Katoh ,Shinji Saito,Shoji Motomizu ,Kentaro Kamiya ,Yoshizumi Miyoshi,Aoi Nakamizo

doi:10.1186/s40623-018-0785-9

Abstract

Understanding of underlying mechanisms of drastic variations of the near-Earth space (geospace) is one of the current focuses of the magnetospheric physics. The science target of the geospace research project Exploration of energization and Radiation in Geospace (ERG) is to understand the geospace variations with a focus on the relativistic electron acceleration and loss processes. In order to achieve the goal, the ERG project consists of the three parts: the Arase (ERG) satellite, ground-based observations, and theory/modeling/integrated studies. The role of theory/modeling/integrated studies part is to promote relevant theoretical and simulation studies as well as integrated data analysis to combine different kinds of observations and modeling. Here we provide technical reports on simulation and empirical models related to the ERG project together with their roles in the integrated studies of dynamic geospace variations. The simulation and empirical models covered include the radial diffusion model of the radiation belt electrons, GEMSIS-RB and RBW models, CIMI model with global MHD simulation REPPU, GEMSIS-RC model, plasmasphere thermosphere model, self-consistent wave–particle interaction simulations (electron hybrid code and ion hybrid code), the ionospheric electric potential (GEMSIS-POT) model, and SuperDARN electric field models with data assimilation. ERG (Arase) science center tools to support integrated studies with various kinds of data are also briefly introduced.

Highlights

The largest disturbances in the near-Earth space are called the magnetic storms or geospace storms, during which the development of the ring current, drastic variation of relativistic electrons in the radiation belts, and intense aurora activities occur (e.g., Williams 1987; Kamide et al 1998; Baker et al 2004)
In “Simulation and empirical models related to the energiza‐ tion and Radiation in Geospace (ERG) project” section, characteristics and limitations of each simulation and empirical model are shown: “Radial diffusion model of the radiation belt electrons,” “Relativistic guiding center test particle (GEMSIS-RB) model,” “Comprehensive Inner Magnetosphere–Ionosphere Model (CIMI) with global MHD simulation REProduce Plasma Universe (REPPU),” “Global drift-kinetic simulation of the ring current: GEMSIS-RC model,” “Plasmasphere thermosphere model (PTM),” “Wave– particle interaction module for GEMSIS-RB (GEMSISRBW model),” “Self-consistent wave–particle interaction simulations,” “A global ionospheric potential solver: GEMSIS-POT,” and “Empirical ionospheric electric field models based on SuperDARN observations and data assimilation.”
Coupling with an ionospheric electric field model based on data assimilation described in “Empirical ionospheric electric field models based on SuperDARN observations and data assimilation” section is planned

Summary

Introduction

The largest disturbances in the near-Earth space (geospace) are called the magnetic storms or geospace storms, during which the development of the ring current, drastic variation of relativistic electrons in the radiation belts, and intense aurora activities occur (e.g., Williams 1987; Kamide et al 1998; Baker et al 2004). The Sheffield University Plasmasphere Ionosphere Model (SUPIM) estimates the densities, field-aligned fluxes, and temperatures of O+ , H+, He+, N2+, O2+, and NO+ ions, and electrons with time-dependent equations of continuity, momentum, and energy balance along eccentric dipole magnetic field lines (Bailey et al 1997).

Results

Conclusion