Jaynes A N, Ali A F, Elkington S R, Malaspina D M, Baker D N, Li X, Kanekal S G, Henderson M G, Kletzing C A, Wygant J R
Department of Physics & Astronomy University of Iowa Iowa City IA USA.
Air Force Research Lab Kirtland Air Force Base Albuquerque NM USA.
Geophys Res Lett. 2018 Oct 28;45(20):10874-10882. doi: 10.1029/2018GL079786. Epub 2018 Oct 25.
Inward radial diffusion driven by ULF waves has long been known to be capable of accelerating radiation belt electrons to very high energies within the heart of the belts, but more recent work has shown that radial diffusion values can be highly event-specific, and mean values or empirical models may not capture the full significance of radial diffusion to acceleration events. Here we present an event of fast inward radial diffusion, occurring during a period following the geomagnetic storm of 17 March 2015. Ultrarelativistic electrons up to ∼8 MeV are accelerated in the absence of intense higher-frequency plasma waves, indicating an acceleration event in the core of the outer belt driven primarily or entirely by ULF wave-driven diffusion. We examine this fast diffusion rate along with derived radial diffusion coefficients using particle and fields instruments on the Van Allen Probes spacecraft mission.
长期以来，人们一直知道由超低频波驱动的向内径向扩散能够将辐射带电子加速到带内核心区域的非常高的能量，但最近的研究表明，径向扩散值可能具有很强的事件特异性，平均值或经验模型可能无法完全体现径向扩散对加速事件的全部意义。在此，我们展示了一次快速向内径向扩散事件，该事件发生在2015年3月17日地磁风暴之后的一段时间内。在没有强烈高频等离子体波的情况下，高达约8兆电子伏的超相对论电子被加速，这表明在外辐射带核心区域发生了一次主要或完全由超低频波驱动的扩散所驱动的加速事件。我们利用范艾伦探测器航天器任务中的粒子和场仪器，研究了这种快速扩散率以及推导得到的径向扩散系数。
