Digitale Medien
[S.l.]
:
American Institute of Physics (AIP)
Physics of Plasmas
5 (1998), S. 836-840
ISSN:
1089-7674
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
Considering the effect of the finite ion gyroradius, the kinetic Alfvén wave in an anisotropic medium driven by a parallel velocity flow was investigated and the full dispersion relation was given. In deducing the dispersion relation, the coupling between electrostatic and electromagnetic oscillations, effects of the resonant electrons and the longitudinal motion of ions are considered. Based on the analytical and numerical calculations, two instability boundaries are found. They are 1〈(k⊥dV0/dx)/kzωci〈νA2/(Ti⊥/mi) and (k⊥dV0/dx)/kzωci〉νA2/(Ti/mi). Resonant electrons serve as the main energy source in these two regimes, while the ion longitudinal motion only suppresses the mode in the second regime. In the boundary layer of the magnetopause, the temperature anisotropy also modifies the instability by lowering the frequency and reducing the growth rate. The above results show that the low-frequency Alfvén waves with the scale of perpendicular wavelengths greater than the ion gyroradius in the magnetopause can be efficiently driven by a velocity-sheared flow. © 1998 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.872650
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