Observations of anomalous transport of energetic electrons in the heliosphere
Observations of anomalous transport of energetic electrons in the heliosphere
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日光层中高能电子异常传输的观测
DOI：
10.5194/astra-4-27-2008
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
G. Zimbardo
中科院分区：
文献类型：
--
作者：
S. Perri;G. Zimbardo
我们研究了由行星际激波加速的高能粒子在激波上游的传播，并考虑了异常传输的可能性。考虑到在超扩散输运的情况下，传播子具有斜率为2<µ< 3的幂律尾部，而对于弹道输运，它在小位移下近似为常数，并且在r 'vt处有一个尖峰，通过传播子形式发展了异常输运的理论处理。我们发现在行进的平面激波中加速的电子的时间分布是幂律而不是指数衰减，这意味着超扩散运动。我们还表明，传播子形式允许描述无散射传播，这可能是在脉冲太阳事件中加速的电子和由WIND观测到的。这些结果表明，高能粒子在太阳风湍流环境中的传播可能是反常的，与最近的数值模拟结果一致，并有望应用于整个日球层的粒子传播。
We study the propagation of energetic particles, accelerated by interplanetary shock waves, upstream of the shock, considering the possibility of having anomalous trans- port. The theoretical treatment of the anomalous transport is developed via the propagator formalism, considering that in the case of a superdiffusive transport the propagator has power law tails with slope 2<µ< 3, while for a ballis- tic transport it is approximately constant for small displace- ments and has a spike for r 'vt. Analyzing a data set from Ulysses spacecraft in the period between July 1992 and November 1993, we find that the time profile of electrons accelerated at a traveling planar shock is a power law rather than an exponential decay, implying superdiffusive motion. We also show that the propagator formalism allows to de- scribe the scatter-free propagation, possible for electrons ac- celerated in impulsive solar events and observed by WIND. These results indicate that the propagation of energetic par- ticles in the turbulent environment of the solar wind can be anomalous, in agreement with the results of recent numerical simulations, and promise to have application to the propaga- tion of particles throughout the heliosphere.