Instituto de Astrofísica de Andalucía, IAA-CSIC, P.O. Box 3004, 18080 Granada, Spain.
Phys Rev Lett. 2014 Jan 31;112(4):045003. doi: 10.1103/PhysRevLett.112.045003. Epub 2014 Jan 29.
We investigate the first example of self-consistent impact ionization fronts propagating at relativistic speeds and involving interacting, high-energy electrons. These fronts, which we name relativistic runaway ionization fronts, show remarkable features such as a bulk speed within less than one percent of the speed of light and the stochastic selection of high-energy electrons for further acceleration, which leads to a power-law distribution of particle energies. A simplified model explains this selection in terms of the overrun of Coulomb-scattered electrons. Appearing as the electromagnetic interaction between electrons saturates the exponential growth of a relativistic runaway electron avalanche, relativistic runaway ionization fronts may occur in conjunction with terrestrial gamma-ray flashes and thus explain recent observations of long, power-law tails in the terrestrial gamma-ray flash energy spectrum.
我们研究了首例以相对论速度传播并涉及相互作用的高能电子的自洽性碰撞离化前沿。我们将这些前沿命名为相对论性 runaway 离化前沿，它们表现出显著的特征，例如速度在光速的不到百分之一内，以及高能电子的随机选择进一步加速，这导致了粒子能量的幂律分布。一个简化的模型根据库仑散射电子的超越来解释这种选择。相对论性 runaway 电子雪崩的电磁相互作用饱和时，就会出现相对论性 runaway 离化前沿，它可能与地面伽马射线闪光照亮，因此可以解释最近观察到的地面伽马射线闪能谱中长的幂律尾巴。
