New chorus wave properties near the equator from Van Allen Probes wave observations
Abstract
The chorus wave properties are evaluated using Van Allen Probes data in the Earth's equatorial magnetosphere. Two distinct modes of lower band chorus are identified: a quasi‐parallel mode and a quasi‐electrostatic mode, whose wave normal direction is close to the resonance cone. Statistical results indicate that the quasi‐electrostatic (quasi‐parallel) mode preferentially occurs during relatively quiet (disturbed) geomagnetic activity at lower (higher) L shells. Although the magnetic intensity of the quasi‐electrostatic mode is considerably weaker than the quasi‐parallel mode, their electric intensities are comparable. A newly identified feature of the quasi‐electrostatic mode is that its frequency peaks at higher values compared to the quasi‐parallel mode that exhibits a broad frequency spectrum. Moreover, upper band chorus wave normal directions vary between 0° and the resonance cone and become more parallel as geomagnetic activity increases. Our new findings suggest that chorus‐driven energetic electron dynamics needs a careful examination by considering the properties of these two distinct modes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 18, 2016
- Source ID
- 10.1002/2016gl068780
Entities
People
- Craig Kletzing
- George G. Hospodarsky
- J. Bortnik
- Ondřej Santolík
- R. M. Thorne
- Wen Li
- William S. Kurth
Organizations
- Air Force Office of Scientific Research
- Charles University
- Institute of Atmospheric Physics AS CR
- Johns Hopkins University Applied Physics Laboratory
- National Aeronautics and Space Administration
- National Science Foundation
- University of California, Los Angeles
- University of Iowa