首页    期刊浏览 2024年11月24日 星期日
登录注册

文章基本信息

  • 标题:Non-thermal electrons at the Earth’s bow shock: A ‘gradual’ event
  • 其他标题:Non-thermal electrons at the Earth’s bow shock: A ‘gradual’ event
  • 本地全文:下载
  • 作者:M. Oka ; T. Terasawa ; M. Fujimoto
  • 期刊名称:Earth, Planets and Space
  • 电子版ISSN:1880-5981
  • 出版年度:2009
  • 卷号:61
  • 期号:5
  • 页码:603-606
  • DOI:10.1186/BF03352932
  • 出版社:Springer Verlag
  • 摘要:The Earth’s bow shock is known to produce non-thermal electrons which are generally observed as a ‘spike’ in their flux profile. Here, in this paper, we present an analysis of electron and whistler wave properties for a quasi-perpendicular shock crossing that is supercritical, but subcritical to the so-called whistler critical Mach number, M w crit , above which whistler waves cannot propagate upstream. We have found that the amplitudes of whistler waves increased exponentially as a function of time prior to the shock encounter, while the suprathermal (>2 keV) electron flux similarly increased with time, although with differing e -folding time scales. Comparison of the electron energy spectrum measured within the ramp with predictions from diffusive shock acceleration theory was poor, but the variation of pitch angle distribution showed scattering of non-thermal electrons in the upstream region. While not finding a specific mechanism to account for the electron diffusion, we suggest that the whistlers seen probably account for the differences observed between this ‘gradual’ event and the ‘spike’ events seen at shocks with no upstream whistlers.
  • 关键词:Particle acceleration ;scattering ;bow shock ;whistlers
国家哲学社会科学文献中心版权所有