Premium
Ion hole formation and nonlinear generation of electromagnetic ion cyclotron waves: THEMIS observations
Author(s) -
Shoji Masafumi,
Miyoshi Yoshizumi,
Katoh Yuto,
Keika Kunihiro,
Angelopoulos Vassilis,
Kasahara Satoshi,
Asamura Kazushi,
Nakamura Satoko,
Omura Yoshiharu
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl074254
Subject(s) - physics , ion , atomic physics , distribution function , cyclotron , electromagnetic radiation , ion acoustic wave , electric field , computational physics , plasma , phase velocity , optics , nuclear physics , quantum mechanics
Abstract Electromagnetic plasma waves are thought to be responsible for energy exchange between charged particles in space plasmas. Such an energy exchange process is evidenced by phase space holes identified in the ion distribution function and measurements of the dot product of the plasma wave electric field and the ion velocity. We develop a method to identify ion hole formation, taking into consideration the phase differences between the gyromotion of ions and the electromagnetic ion cyclotron (EMIC) waves. Using this method, we identify ion holes in the distribution function and the resulting nonlinear EMIC wave evolution from Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. These ion holes are key to wave growth and frequency drift by the ion currents through nonlinear wave‐particle interactions, which are identified by a computer simulation in this study.