Premium
Stochastic ion heating at the magnetopause due to kinetic Alfvén waves
Author(s) -
Johnson Jay R.,
Cheng C. Z.
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl013509
Subject(s) - magnetopause , physics , magnetosheath , gyroradius , amplitude , computational physics , kinetic energy , wavelength , magnetosphere , ion , atomic physics , boundary layer , cyclotron , geophysics , magnetic field , mechanics , classical mechanics , optics , quantum mechanics
The magnetopause and boundary layer are typically characterized by large amplitude transverse wave activity with frequencies below the ion cyclotron frequency. The signatures of the transverse waves suggest that they are kinetic Alfvén waves with wavelength on the order of the ion gyroradius [ Johnson and Cheng, 1997a; Johnson et al., 2001]. We investigate ion motion in the presence of large amplitude kinetic Alfvén waves with wavelength the order of ρ i and demonstrate that for sufficiently large wave amplitude (δ B ⟂ / B 0 > 0.05) the particle orbits become stochastic. As a result, low energy particles in the core of the ion distribution can migrate to higher energy through the stochastic sea leading to an increase in T ⟂ and a broadening of the distribution. This process can explain transverse ion energization and formation of conies which have been observed near the magnetopause in both the magnetosheath and low‐latitude boundary layer.