Journal article
Statistical characteristics of EMIC waves: Van Allen Probe observations
Journal of geophysical research. Space physics, Vol.120(6), pp.4400-4408
06/2015
DOI: 10.1002/2015JA021089
Abstract
Utilizing the data from the magnetometer instrument which is a part of the Electric and Magnetic Field Instrument Suite and Integrated Science instrument suite on board the Van Allen Probe A from September 2012 to April 2014, when the apogee of the satellite has passed all the magnetic local time (MLT) sectors, we obtain the statistical distribution characteristics of electromagnetic ion cyclotron (EMIC) waves in the inner magnetosphere over all magnetic local times from L = 3 to L = 6. Compared with the previous statistical results about EMIC waves, the occurrence rates of EMIC waves distribute relatively uniform in the MLT sectors in lower L shells. On the other hand, in higher L shells, there are indeed some peaks of the occurrence rate for the EMIC waves, especially in the noon, dusk, and night sectors. EMIC waves appear at lower L shells in the dawn sector than in other sectors. In the lower L shells (L < 4), the occurrence rates of EMIC waves are significant in the dawn sector. This phenomenon may result from the distribution characteristics of the plasmasphere. The location of the plasmapause is usually lower in the dawn sector than that in other sectors, and the plasmapause is considered to be the favored region for the generation of EMIC waves. In higher L shells (L > 4) the occurrence rates of EMIC waves are most significant in the dusk sector, implying the important role of the plasmapause or plasmaspheric plume in generating EMIC waves. We have also investigated the distribution characteristics of the hydrogen band and the helium band EMIC waves. Surprisingly, in the inner magnetosphere, the hydrogen band EMIC waves occur more frequently than the helium band EMIC waves. Both of them have peaks of occurrence rate in noon, dusk, and night sectors, and the hydrogen band EMIC waves have more obvious peaks than the helium band EMIC waves in the night sector, while the helium band EMIC waves are more concentrated than the hydrogen band EMIC waves in the dusk sector. Both of them occur significantly in the noon sector, which implies the important role of the solar wind dynamic pressure.
Details
- Title: Subtitle
- Statistical characteristics of EMIC waves: Van Allen Probe observations
- Creators
- Dedong Wang - Wuhan UniversityZhigang Yuan - Wuhan UniversityXiongdong Yu - Wuhan UniversityXiaohua Deng - Wuhan UniversityMeng Zhou - Nanchang UniversityShiyong Huang - Wuhan UniversityHaimeng Li - Wuhan UniversityZhenzhen Wang - Wuhan UniversityZheng Qiao - Wuhan UniversityC. A Kletzing - University of IowaJ. R Wygant - University of Minnesota
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.120(6), pp.4400-4408
- DOI
- 10.1002/2015JA021089
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Grant note
- DOI: 10.13039/501100001809, name: National Natural Science Foundation of China, award: 41374168, 41174140, 41174147; name: Fund for the Doctoral Program of Higher Education of China, award: 20110141110043; DOI: 10.13039/501100012226, name: Fundamental Research Funds for the Central Universities of China, award: 2012212020204; DOI: 10.13039/501100004602, name: Program for New Century Excellent Talents in University, award: NCET-13-0446; name: Science Foundation of Jiangxi Province, award: 20142BCB23006
- Language
- English
- Date published
- 06/2015
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199929302771
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