首页 | 本学科首页   官方微博 | 高级检索  
     检索      


HF wave activity in the low and middle-altitude polar cusp
Authors:H Rothkaehl  J-G Trotignon  P Decreau  J B?ecki  F Pitout  H Reme
Institution:1. Space Research Centre PAS 00-716 Warsaw, Bartycka 18A, Poland;2. LPCE/CNRS, 3A avenue de la Recherche Scientifique 45071, Orleans Cedex 2, France;3. ESA/ESTEC, Postbus 299, 2200 AG Noordwijk, Nordwijk, The Netherlands;4. CESR CNRS, Avenue Colonel, Roche 9, 31029 Toulouse, Cedex, France
Abstract:We reported the results of our investigations of wave activity in high-frequency range performed on board CLUSTER spacecraft in the middle-altitude cusp region, around 5 RE during August and September 2002. Our analysis was mainly based on the registration gathered by the WHISPER instrument (Waves of HIgh frequency and Sounder for Probing of Electron density by Relaxation). For a better understanding of the processes of wave-particle interaction and in order to understand the general plasma conditions in the cusp region, we also included in our analysis the data registered by the STAFF (Spatio-Temporal Analysis of Field Fluctuation experiment) instrument and the CIS (Ion Spectrometry experiment) instrument. These observations were carried out during different geomagnetic activity; under quiet conditions and during magnetic storm period. The space plasma is characterised by the ratio of plasma frequency to electron gyrofrequency, in this case, the local plasma frequency was, mainly, a little greater than the electron plasma, but it was also frequently observed that these two characteristic frequencies were not very different from one another. The whistler waves, electron-cyclotron waves, electron-acoustic waves and Langmuir waves have been detected when the spacecraft was crossing the middle-altitude cusp region. We suggested that the majority of those waves were generated by electron beams. For a better understanding the plasma conditions in the low and middle-altitude cusp region the past FREJA wave data results are used to describe typical wave activity detected in the low-altitude cusp region. The aim of this paper is to discuss, on the basis of a few chosen representative examples, the property of typical high wave activity detected in the lower part of cusp region.
Keywords:Middle and low-altitude cusp  HF wave activity
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号