Alfvenic plasma velocity variations observed at the inner edge of the low-latitude boundary layer induced by the magnetosheath mirror mode waves: A THEMIS observation

作者：Nowada M^*; Shue J H; Lin C H; Sakurai T; Sibeck D G; Angelopoulos V; Carlson C W; Auster H U

来源：Journal of Geophysical Research, 2009, 114(A7): A07208.

DOI：10.1029/2008JA014033

With unique simultaneous observations both in the magnetosheath and magnetosphere by the THEMIS probes, Alfvenic variations in the plasma velocity are observed at the inner edge of low-latitude boundary layer (LLBL) and are induced by the mirror mode waves in the magnetosheath near the subsolar magnetopause on 31 July 2007. These Alfvenic variations appeared as the wavy perturbations in the V(x) and V(y) components observed by THEMIS C, D, and E, which had the same periodicity as associated magnetic field variations. Simultaneously, THEMIS B observed the mirror mode waves in the magnetosheath. The periodicities of the magnetic and plasma pressure variations of mirror modes in the magnetosheath were consistent with those of the Alfvenic wavy variations in the LLBL. Therefore, the mirror mode waves can induce the magnetopause undulations, launching Alfven waves, and resultant Alfvenic variations are observed in the LLBL. Also, in the succeeding magnetosheath interval by THEMIS B, we examined whether the mirror mode waves occurred and associated Alfvenic variations were observed in the LLBL. However, no clear evidence for an existence of the mirror mode waves was obtained, and THEMIS C, D, and E do not also observe associated magnetic field and plasma Alfvenic responses in the LLBL. These results suggest that the Alfvenic variations in the LLBL are strongly related to the mirror mode waves in the magnetosheath. On the basis of these results, we emphasize that the magnetosheath energy is transmitted and transported into the magnetosphere via magnetopause surface waves.

• 出版日期2009-7-9
• 单位中央民族大学