Time domain structures: What and where they are, what they do, and how they are made
Time domain structures: What and where they are, what they do, and how they are made
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DOI：
10.1002/2015gl063946
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发表时间：
2015-05-28
影响因子：
5.2
通讯作者：
Vasko, I.
中科院分区：
文献类型：
--
作者：
Mozer, F. S.;Agapitov, O. V.;Vasko, I.
时域结构（TDS）（静电或电磁电子空穴、孤波、双层等）是具有显著平行（与背景磁场）电场的1ms脉冲。他们是丰富的通过空间和发生在数百包的外部货车艾伦辐射带，在那里他们产生磁场对齐的电子俯仰角分布在能量高达100千电子伏。TDS可以提供种子电子，这些种子电子后来被哨声加速到相对论能量，它们还产生场对准电子，这可能是某些类型极光的原因。这些场对准的电子分布至少由三个过程产生。第一个过程是在TDS平行电场中通过朗道捕获的平行加速。第二个过程是由于TDS反射电子而产生的费米加速。第三个过程是一个有效的和快速的俯仰角散射所产生的电子相互作用与垂直和平行的电场和磁场的许多TDS。TDS是由电流驱动和光束相关的不稳定性和哨声相关的过程，如参数衰减的哨声和非线性演化从斜哨声。关于TDS与粒子注入的时间关系、TDS产生的场向电子俯仰角分布类型、TDS产生场向分布的机制、TDS在没有哨声模式波的情况下产生的场向电子的最大能量、倾斜哨声和三波参数衰减产生TDS以及TDS与极光粒子沉淀之间的相关性的新结果，给出了
Time domain structures (TDS) (electrostatic or electromagnetic electron holes, solitary waves, double layers, etc.) are 1ms pulses having significant parallel (to the background magnetic field) electric fields. They are abundant through space and occur in packets of hundreds in the outer Van Allen radiation belts where they produce magnetic-field-aligned electron pitch angle distributions at energies up to a hundred keV. TDS can provide the seed electrons that are later accelerated to relativistic energies by whistlers and they also produce field-aligned electrons that may be responsible for some types of auroras. These field-aligned electron distributions result from at least three processes. The first process is parallel acceleration by Landau trapping in the TDS parallel electric field. The second process is Fermi acceleration due to reflection of electrons by the TDS. The third process is an effective and rapid pitch angle scattering resulting from electron interactions with the perpendicular and parallel electric and magnetic fields of many TDS. TDS are created by current-driven and beam-related instabilities and by whistler-related processes such as parametric decay of whistlers and nonlinear evolution from oblique whistlers. New results on the temporal relationship of TDS and particle injections, types of field-aligned electron pitch angle distributions produced by TDS, the mechanisms for generation of field-aligned distributions by TDS, the maximum energies of field-aligned electrons created by TDS in the absence of whistler mode waves, TDS generation by oblique whistlers and three-wave-parametric decay, and the correlation between TDS and auroral particle precipitation, are presented.