Turbulent heating and cross-field transport near the magnetopause from THEMIS

被引:71
|
作者
Chaston, C. [1 ]
Bonnell, J. [1 ]
McFadden, J. P. [1 ]
Carlson, C. W. [1 ]
Cully, C. [5 ]
Le Contel, O. [4 ]
Roux, A. [4 ]
Auster, H. U. [3 ]
Glassmeier, K. H. [3 ]
Angelopoulos, V. [2 ]
Russell, C. T. [2 ]
机构
[1] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
[2] Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA
[3] Tech Univ Carolo Wilhelmina Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany
[4] Ctr Etud Environm Terr & Planetaires, F-78140 Velizy Villacoublay, France
[5] Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA
关键词
D O I
10.1029/2008GL033601
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
We demonstrate that the low frequency broadband magnetic fluctuations observed during THEMIS spacecraft traversals near the Earth's magnetopause may be described as a turbulent spectrum of Doppler shifted kinetic Alfven waves (KAWs). These waves are most intense along reconnected flux-tubes in the magnetosheath just outside the magnetopause. We identify distinct power-law scalings of wave spectral energy density in wavenumber and show that Landau ( LD) and transit time damping (TD) on ions and electrons is largest at the wavenumber where the power-law index changes. The threshold amplitude for stochastic ion scattering/ acceleration is also exceeded by these waves. These acceleration processes are manifest in observations of field-aligned and transverse heating of electrons and ions respectively. From integration over the range of observed wavenumbers we show that, if the wave-normal angles are sufficiently large, these waves can provide diffusive transport of magnetosheath plasmas across the magnetopause at up to the Bohm rate.
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页数:5
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