Dissipation range dynamics: Kinetic Alfvén waves and the importance of βe
Abstract
In a previous paper we argued that the damping of obliquely propagating kinetic Alfvén waves, chiefly by resonant mechanisms, was a likely explanation for the formation of the dissipation range for interplanetary magnetic field fluctuations. This suggestion was based largely on observations of the dissipation range at 1 AU as recorded by the Wind spacecraft. We pursue this suggestion here with both a general examination of the damping of obliquely propagating kinetic Alfvén waves and an additional examination of the observations. We explore the damping rates of kinetic Alfvén waves under a wide range of interplanetary conditions using numerical solutions of the linearized Maxwell-Vlasov equations and demonstrate that these waves display the nearly isotropic dissipation properties inferred from the previous paper. Using these solutions, we present a simple model to predict the onset of the dissipation range and compare these predictions to the observations. In the process we demonstrate that electron Landau damping plays a significant role in the damping of interplanetary magnetic field fluctuations which leads to significant heating of the thermal electrons.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- October 1999
- DOI:
- 10.1029/1999JA900158
- Bibcode:
- 1999JGR...10422331L
- Keywords:
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- Solar Physics;
- Astrophysics;
- and Astronomy