EMIC Waves Converted From Equatorial Noise Due to M/Q=2 Ions in the Plasmasphere: Observations From Van Allen Probes and Arase

被引：36

作者：

Miyoshi, Y. ^{[1
]}

Matsuda, S. ^{[2
]}

Kurita, S. ^{[1
]}

Nomura, K. ^{[1
]}

Keika, K. ^{[3
]}

Shoji, M. ^{[1
]}

Kitamura, N. ^{[3
]}

Kasahara, Y. ^{[4
]}

Matsuoka, A. ^{[2
]}

Shinohara, I. ^{[2
]}

Shiokawa, K. ^{[1
]}

Machida, S. ^{[1
]}

Santolik, O. ^{[5
,6
]}

Boardsen, S. A. ^{[7
,8
]}

Horne, R. B. ^{[9
]}

Wygant, J. F. ^{[10
]}

机构：

[1] Nagoya Univ, ISEE, Nagoya, Aichi, Japan

[2] ISAS JAXA, Sagamihara, Kanagawa, Japan

[3] Univ Tokyo, Grad Sch Sci, Tokyo, Japan

[4] Kanazawa Univ, Grad Sch Nat Sci & Technol, Kanazawa, Ishikawa, Japan

[5] Czech Acad Sci, Inst Atmospher Phys, Dept Space Phys, Prague, Czech Republic

[6] Charles Univ Prague, Fac Math & Phys, Prague, Czech Republic

[7] Univ Maryland Baltimore Cty, Goddard Planetary Heliophys Inst, Baltimore, MD 21228 USA

[8] NASA, Goddard Space Flight Ctr, Greenbelt, MD USA

[9] British Antarctic Survey, Cambridge, England

[10] Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA

来源：

GEOPHYSICAL RESEARCH LETTERS | 2019年 / 46卷 / 11期

基金：

英国自然环境研究理事会; 日本学术振兴会;

关键词：

EMIC; magnetsonic waves; Arase; Van Allen Probes; plasmasphere; M; Q=2 ions; MAGNETOSONIC WAVES; SATELLITE AKEBONO; CYCLOTRON WAVES; PROPAGATION; EMISSIONS; MAGNETOSPHERE; WHISTLER; FREQUENCY; EXCITATION; VICINITY;

D O I：

10.1029/2019GL083024

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

Equatorial noise (EN) emissions are observed inside and outside the plasmapause. EN emissions are referred to as magnetosonic mode waves. Using data from Van Allen Probes and Arase, we found conversion from EN emissions to electromagnetic ion cyclotron (EMIC) waves in the plasmasphere and in the topside ionosphere. A low-frequency part of EN emissions becomes EMIC waves through branch splitting of EN emissions, and the mode conversion from EN to EMIC waves occurs around the frequency of M/Q = 2 (deuteron and/or alpha particles) cyclotron frequency. These processes result in plasmaspheric EMIC waves. We investigated the ion composition ratio by characteristic frequencies of EN emissions and EMIC waves and obtained ion composition ratios. We found that the maximum composition ratio of M/Q = 2 ions is similar to 10% below 3,000 km. The quantitative estimation of the ion composition will contribute to improving the plasma model of the deep plasmasphere and the topside ionosphere.

引用

页码：5662 / 5669

页数：8

共 44 条

[1] FUNNEL-SHAPED, LOW-FREQUENCY EQUATORIAL WAVES [J].