Synchrotron Emission from Particles Having A Truncated Power-law Energy Spectrum
Synchrotron Emission from Particles Having A Truncated Power-law Energy Spectrum
复制标题
具有截断幂律能谱的粒子的同步辐射
DOI：
10.1093/mnras/168.2.379
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发表时间：
1974
影响因子：
4.8
通讯作者：
K. Westfold
中科院分区：
文献类型：
--
作者：
L. J. Gleeson;M. Legg;K. Westfold
已经确定了在均匀磁场中运动的超相对论性带电粒子的同步辐射的频谱，其总能量呈幂律分布，有上限和下限。还考虑到单个粒子不能辐射低于其基本回旋频率的事实。导出了用于确定Stokes参数的级数，并将结果作为校正因子应用于Legg & Westfold确定的光谱，当最大发射率能量位于（E1,E2）范围内时，这些系数仍然有效。与未校正谱的线性形式（在对数-对数显示上）相反，当e2 =∞时，完整谱具有三个特征线性部分，并且当e2为有限时，被限制在相应的上下频率之间。这三段涵盖了很宽的频率范围，从O（fc1）及以上，其中efc1为下限截止能量对应的临界频率；在最低波段，它们应被视为指示光谱的趋势。然而，在实际情况下，对这些部分之间的跃迁频率的观察将有助于得出关于te1和磁场强度的有用推断。本文的结果为确定当前感兴趣的更复杂的情况下的完整辐射谱提供了基础，例如木星行星偶极磁场中捕获的电子的辐射。
The frequency spectrum has been determined of the synchrotron emission from ultra-relativistic electrically charged particles moving in a uniform magnetic field and having a power-law distribution in total energyEwhich has upper and lower limitsE1,E2. Account is taken also of the fact that a single particle cannot radiate below its fundamental gyrofrequency. Series have been derived for the determination of the Stokes parameters and the results presented as correction factors to be applied to the spectra determined by Legg & Westfold, which remain valid when the energy of maximum emissivity lies well within the range (E1,E2). In contrast with the linear form (on a log–log display) of the uncorrected spectra, the complete spectra have three characteristic linear sections whenE2= ∞ and, in addition whenE2is finite, are confined between corresponding upper and lower frequencies. These three sections cover a wide range of frequencies, fromto O(fc1) and above, wherefc1is the critical frequency corresponding to the lower cut-off energyE1; in the lowest band they should be taken as indicating the trends of the spectra. Nevertheless, in a practical situation, observations of the transition frequencies between these sections would enable useful inferences aboutE1and the magnetic-field intensity to be drawn.The results of this paper provide the basis for determining the complete radiation spectrum in more complex cases of current interest, e.g. the radiation from electrons trapped in the dipolar magnetic field of the planet Jupiter.