کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1776431 | 1523614 | 2015 | 9 صفحه PDF | دانلود رایگان |
• Larger-amplitude electromagnetic waves were observed at DF.
• Electromagnetic waves belong to Ion Bernstein mode or current-driven ion cyclotron mode.
• The observed electromagnetic waves cannot accelerate the protons at the survival timescale of the DFs and the waves.
Broadband frequency waves around the dipolarization front (DF) are believed to play a crucial role in the particle dynamics. Using the Cluster observations, we report in this study large-amplitude electromagnetic waves with frequencies just above the ion cyclotron frequency at the DF in the near-Earth magnetotail region. The waves have very large amplitudes of magnetic and electric field fluctuations, up to ~2 nT and ~10 mV/m, respectively. The magnetic fluctuations are predominately along the ambient magnetic field (B0), while the electric fluctuations are primarily perpendicular to B0. The observed waves are highly oblique with a propagation angle of ~100° with respect to the ambient magnetic field, and are also linearly polarized. These features are consistent with the properties of the ion Bernstein wave mode in the high plasma β region, and also with the properties of current-driven ion cyclotron waves driven by the electromagnetic current-driven Alfven instability. We also discuss the possibility of wave–particle interactions at the DF.
Journal: Journal of Atmospheric and Solar-Terrestrial Physics - Volume 129, July 2015, Pages 119–127