A role of cosmic rays in generation of radio and optical radiation by plasma mechanisms
A role of cosmic rays in generation of radio and optical radiation by plasma mechanisms
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DOI：
10.1007/bf00641755
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发表时间：
1987-04
影响因子：
1.9
通讯作者：
I. N. Toptygin;G. Fleishman
中科院分区：
文献类型：
--
作者：
I. N. Toptygin;G. Fleishman
超相对论粒子的辐射检查在一个准均匀的磁场叠加了广泛的频谱的磁，电，和电子密度不均匀性在湍流等离子体中创建。具有给定能量的粒子的辐射谱显示出获得高频幂律尾部，其谱指数与小尺度湍流的指数ν相同。超相对论性电子的幂律谱dN（λ）/d λ ~ λ − λ，在某一能量λ max处截止，辐射谱由几个幂律范围组成;辐射强度可能在分隔这些范围的频率处发生跳跃。在高频范围内，谱指数ν由小尺度磁场和电场决定。在中频，主要贡献来自大尺度场中的同步辐射;辐射谱的指数为α=（λ −1）/2。大尺度朗缪尔波也可以产生相同的折射率。在较低的频率下，由于电子密度涨落引起的跃迁辐射，辐射谱增加;在这种情况下，谱指数等于π +1 −ν。讨论了从高能粒子辐射诊断高频宇宙等离子体湍流的可能性。结果表明，所提出的理论可以解释一些宇宙天体的光谱特征。
The radiation of ultrarelativistic particles is examined in a quasi-uniform magnetic field superimposed by a wide spectrum of magnetic, electric, and electron density inhomogeneities created in a turbulent plasma. The radiation spectrum from a particle of a given energy is shown to acquire a high-frequency power-law tail with the same spectral index as the index ν of small-scale turbulence. For a power-law spectrum of ultrarelativistic electrons, dN(ℰ)/dℰ ~ ℰ−ξ, with a cut-off at some energy ℰmax, the radiation spectrum consists of a few power-law ranges; the radiation intensity may suffer jumps at frequencies which separate these ranges.In the high-frequency range the spectral index ν is determined by small-scale magnetic and electric fields. At intermediate frequencies the main contribution comes from the synchrotron radiation in a large-scale field; the radiation spectrum has an index α=(ζ−1)/2. The same index may be produced by large-scale Langmuir waves. At lower frequencies the radiation spectrum increases owing to the transition radiation caused by electron density fluctuations; in this case the spectral index is equal to ζ+1−ν.The possibility of diagnostics of high-frequency cosmic plasma turbulence from radiation of high-energy particles is discussed. It is shown that the proposed theory may explain some features in the spectra of several cosmic objects.