共 3 条
Spatio-temporal structure of Alfven waves excited by a sudden impulse localized on an L-shell
被引:10
作者:
Klimushkin, D. Yu.
[1
]
Mager, P. N.
[1
]
Glassmeier, K. -H.
[2
]
机构:
[1] Russian Acad Sci, Siberian Branch, Inst Solar Terr Phys, Irkutsk 664033, Russia
[2] Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany
关键词:
Magnetospheric physics;
MHD waves and instabilities;
KELVIN-HELMHOLTZ INSTABILITY;
PERIOD MAGNETIC PULSATIONS;
AXISYMMETRICAL MAGNETOSPHERE;
PLASMA INHOMOGENEITY;
MHD WAVES;
MAGNETOPAUSE;
OSCILLATIONS;
GENERATION;
EXCITATION;
PARTICLES;
D O I:
10.5194/angeo-30-1099-2012
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
This paper is concerned with the spatial structure and temporal evolution of the azimuthally small scale Alfv,n wave generated by a sudden impulse concentrated on a given magnetic shell. At the outset, both poloidal and toroidal components are present in the wave's magnetic field. The oscillation in the poloidal component on a given magnetic shell is a superposition of two monochromatic oscillations, one with the local resonance frequency on this shell, and the other with the frequency corresponding to the resonance frequency on the source surface. The superposition of these two oscillations leads to beating. Due to phase mixing, the poloidal component of the oscillation decreases with time down to zero, transferring its energy to the toroidal component. Beating in the toroidal component is less pronounced. As time elapses, energy concentration near the source magnetic shell occurs with the frequency of the oscillation corresponding to the Alfv,nic resonance frequency on this surface. Outside this thin region wave amplitudes become rather small at oscillation frequencies corresponding to the local resonance frequency of the respective magnetic shell.
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页码:1099 / 1106
页数:8
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