Spontaneous emission of Alfven waves and its role in generation of Alfven turbulence
会议名称：《第十四届全国日地空间物理学术研讨会》
会议日期：2011年
学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学]
摘 要：Alfven turbulence is ubiquitous low-frequency electromagnetic fluctuations in space and astrophysical environments. There are rich free-energy sources of exciting Alfven waves due to instabilities in space and astrophysical plasmas. In plasma physics literature there are numerous discussions in which relevant reactive instabilities are extensively investigated. These theories of instability, however, are mainly interested in the discussion whether a perturbation will grow or be damped under a given unperturbed velocity distribution. Few papers elaborate the meaning of growth or amplification in terms of initial perturbation. In this letter, we extend the discussion of Alfven-wave beam instability by including the effect of spontaneous generation of the waves, which can effectively plays the role of an initial perturbation.