Weak turbulence in the magnetosphere: Formation of whistler wave cavity by nonlinear scattering

Author
Keywords
Abstract
We consider the weak turbulence of whistler waves in the in low-β inner magnetosphere of the earth. Whistler waves, originating in the ionosphere, propagate radially outward and can trigger nonlinear induced scattering by thermal electrons provided the wave energy density is large enough. Nonlinear scattering can substantially change the direction of the wave vector of whistler waves and hence the direction of energy flux with only a small change in the frequency. A portion of whistler waves return to the ionosphere with a smaller perpendicular wave vector resulting in diminished linear damping and enhanced ability to pitch-angle scatter trapped electrons. In addition, a portion of the scatteredwave packets can be reflected near the ionosphere back into the magnetosphere. Through multiple nonlinear scatterings and ionospheric reflections a long-lived wavecavity containing turbulent whistler waves can be formed with the appropriate properties to efficiently pitch-angle scatter trapped electrons. The primary consequence on the earth\textquoterights radiation belts is to reduce the lifetime of the trapped electron population.
Year of Publication
2012
Journal
Physics of Plasmas
Volume
19
Number of Pages
032903
Date Published
01/2012
ISSN Number
1070664X
URL
http://scitation.aip.org/content/aip/journal/pop/19/3/10.1063/1.3692092
DOI
10.1063/1.3692092