Open AccessThe eigenmode of solitary kinetic Alfvén waves observed by Freja satellite
Author(s) -
Huang GuangLi,
Wang DeYu,
Wu DeJin,
Féraudy H.,
Le Quéau D.,
Volwerk M.,
Holback Bengt
Publication year - 1997
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/96ja02607
Subject(s) - physics , amplitude , phase velocity , polarization (electrochemistry) , cyclotron , electric field , computational physics , normal mode , magnetic field , phase (matter) , anisotropy , magnetosphere , ultra low frequency , kinetic energy , alfvén wave , classical mechanics , magnetohydrodynamics , optics , quantum mechanics , astronomy , vibration , chemistry
The properties of the solitary kinetic Alfvén waves (SKAWs) observed by Freja satellite are studied statistically for a typical event on March 7, 1994. The eigenmode of the SKAWs observed is still recognized by their anisotropic structure (1000 km × 1 km), their waveform which is similar to that of a wave packet and their frequency close to the local oxygen ion cyclotron frequency. If these spatial structures really exist, they may have resulted from the evolution of the SKAWs or some envelope solitons of ion cyclotron and magnetosonic waves, which is supported by four statistical results: (1) The phase velocity is directly proportional to the Alfvén velocity. (2) The amplitudes of the electric filed, magnetic field and density fluctuations are directly proportional to the timescales of the pulsations. (3) The amplitudes as well as the timescales are directly proportional to the phase velocity. (4) The polarization sense is both of right circular and left circular mode with different phase relation among the electric field, magnetic field, and density fluctuations. Moreover, the SKAWs are often superposed by a strong electrostatic fluctuations at several hundred hertz, the causal relation between the SKAWs and superposed waves is still unknown.