## Abstract

In the upcoming JAXA/ERG satellite mission, Wave Particle Interaction Analyzer (WPIA) will be installed as an onboard software function. We study the statistical significance of the WPIA for measurement of the energy transfer process between energetic electrons and whistler-mode chorus emissions in the Earth's inner magnetosphere. The WPIA measures a relative phase angle between the wave vector E and velocity vector ν of each electron and computes their inner product W, where W is the time variation of the kinetic energy of energetic electrons interacting with plasma waves. We evaluate the feasibility by applying the WPIA analysis to the simulation results of whistler-mode chorus generation. We compute W using both a wave electric field vector observed at a fixed point in the simulation system and a velocity vector of each energetic electron passing through this point. By summing up W_{i} of an individual particle i to give W_{int}, we obtain significant values of W_{int} as expected from the evolution of chorus emissions in the simulation result.We can discuss the efficiency of the energy exchange through wave-particle interactions by selecting the range of the kinetic energy and pitch angle of the electrons used in the computation of W_{int}. The statistical significance of the obtained W_{int} is evaluated by calculating the standard deviation σ_{W} of W_{int}. In the results of the analysis, positive or negative W_{int} is obtained at the different regions of velocity phase space, while at the specific regions the obtained W_{int} values are significantly greater than σ_{W}, indicating efficient wave-particle interactions. The present study demonstrates the feasibility of using the WPIA, which will be on board the upcoming ERG satellite, for direct measurement of wave-particle interactions.

Original language | English |
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Pages (from-to) | 503-512 |

Number of pages | 10 |

Journal | Annales Geophysicae |

Volume | 31 |

Issue number | 3 |

DOIs | |

Publication status | Published - 2013 Mar 19 |

Externally published | Yes |

## Keywords

- Magnetospheric physics (Plasma waves and instabilities)
- Space plasma physics (Wave-particle interactions; Instruments and techniques)

## ASJC Scopus subject areas

- Astronomy and Astrophysics
- Geology
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science