TY - JOUR
T1 - Ion hole formation and nonlinear generation of electromagnetic ion cyclotron waves
T2 - THEMIS observations
AU - Shoji, Masafumi
AU - Miyoshi, Yoshizumi
AU - Katoh, Yuto
AU - Keika, Kunihiro
AU - Angelopoulos, Vassilis
AU - Kasahara, Satoshi
AU - Asamura, Kazushi
AU - Nakamura, Satoko
AU - Omura, Yoshiharu
N1 - Funding Information:
We acknowledge NASA contract NAS5-02099 for use of data from the THEMIS Mission. THEMIS data are obtained at http://themis.ssl. berkeley.edu/data/themis/. All the new simulation data used in this paper are obtained from numerical integration of the equations of motion of ions and Maxwell’s equations. Since the simulation data size is too huge, we will provide the data on request. Computations were performed using the KDK system of Research Institute for Sustainable Humanosphere and Academic Center for Computing and Media Studies at Kyoto University as a collaborative research project. Part of this work was done at the ERG-Science Center operated by ISAS/JAXA and ISEE/Nagoya University. This study was supported by Grants-in-Aid for Scientific Research (26800256, 26287120, 23340146, 25287127, 26800257, 23224011, 15H05815, 15H05747, 15H03730, and 17K14402) of the Ministry of Education, Culture, Sports, Science, and Technology in Japan. This work is also supported by JSPS Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers under grant G2602. V.A. was funded by NASANAS5-02099. We also thank Judy Hohl for her valuable suggestions on improving the paper.
Publisher Copyright:
©2017. American Geophysical Union. All Rights Reserved.
PY - 2017/9/16
Y1 - 2017/9/16
N2 - 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.
AB - 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.
KW - THEMIS observation
KW - hybrid simulation
KW - nonlinear wave growth
KW - wave-particle interaction
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U2 - 10.1002/2017GL074254
DO - 10.1002/2017GL074254
M3 - Article
AN - SCOPUS:85029445610
SN - 0094-8276
VL - 44
SP - 8730
EP - 8738
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 17
ER -