Auroral Kilometric Radiation and Transverse Acceleration of Ions in Ionosphere Magnetosphere Plasmas

这一提议的目的是解释极光公里辐射(AKR)的一些观测特性，并了解导致电离层离子(TAI)横向加速的一些过程，这些离子最终填充在地球磁层中，并导致强烈的电离层-磁层耦合。用于实现这一建议目标的分析和计算技术包括等离子体中不稳定性的时空演化，以及离子动力学中的波诱导混沌，其中包括网络随机性的新概念。近二十年来，AKR在观测和理论上一直是一个令人着迷和广泛研究的来源。在此期间积累的数据已经提供了关于AKR源区、波的模式和极化以及存在于震源区及其周围的粒子分布的信息。人们普遍认为，由于AKR的辐射功率比热发射高出几个数量级，因此AKR的来源是等离子体不稳定性。基于损失锥电子分布产生的电子回旋脉泽不稳定性(ECMI)的理论已经成功地解释了AKR的一些观测性质。因此，ECMI通常被认为是AKR的来源。然而，传统的ECMI分析未能对AKR的一些与观测相一致的重要特征提供明确的解释。拟议的工作意在理解和解释尚未从理论上理解的具体现象。电离层-磁层强烈耦合的一个特征是过去15年中报道的一系列观测，这些观测表明，磁层等离子体中的相当大一部分离子来自电离层。在电离层中，观察到离子在横穿地磁场的方向上被加速。离子和等离子体波之间的相互作用似乎存在于TAI发生的区域，被认为在TAI中发挥了重要作用。这项研究将利用非线性动力学和网络随机性的概念来理解低杂波波包对离子的加速；观测到的O+的尾部加热和H+的整体加热；在TAI期间观察到的离子分布函数。

The aim of this proposal is to explain some of the observed properties of the auroral kilometric radiation (AKR), and to understand some of the processes leading to the transverse acceleration of ionospheric ions (TAI) that eventually populate the Earth's magnetosphere and result in a strong ionosphere- magnetosphere coupling. The analytical and computational techniques that will be used to attain the goals of this proposal include the space-time evolution of instabilities in plasmas, and wave induced chaos in ion dynamics including the novel concept of web stochasticity. AKR has been a source of fascination and extensive study, observationally and theoretically, for nearly twenty years. The data accumulated during this period has provided information about the AKR source regions, the modes and polarizations of the waves, and the particle distributions that exist in and around the source regions. It is generally agreed upon that, since the radiated power in AKR is orders of magnitude above thermal emissions, the source of AKR is plasma instabilities. Theories based upon the electroncyclotron maser instabilities (ECMI), generated by loss- cone electron distributions, have been successful in explaining some of the observed properties of AKR. Thus, ECMI are generally believed to be the source of AKR. However, the traditional analyses of ECMI have failed to provide a clear explanation of some of the important features of AKR that are consistent with observations. The proposed work intends to understand and explain the specific phenomena that have not yet been understood theoretically. A signature of the strong ionosphere-magnetosphere coupling is a series of observations, reported over the past fifteen years, which show that a significant population of the ions in the magnetospheric plasma are of ionospheric origin. In the ionosphere, the ions are observed to be accelerated in a direction transverse to the geomagnetic field. The interaction between ions and plasma waves, that seem to be present in regions where TAI occurs, is believed to play an important role in the TAI. The proposed research is to use concepts of nonlinear dynamics and web stochasticity to understand the acceleration of ions by lower- hybrid wave packets; the observed tail heating of O+ and bulk heating of H+; the ion distribution functions observed during TAI.