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

本建议的目的是解释一些观测到的极光千米辐射（AKR）的特性，并了解导致电离层离子（TAI）横向加速的一些过程，这些离子最终填充地球磁层并导致电离层-磁层的强耦合。为了达到这个建议的目标，将使用的分析和计算技术包括等离子体不稳定性的时空演化，以及离子动力学中的波致混沌，包括新的网络随机性概念。近二十年来，无论是在观测上还是理论上，AKR一直是一个令人着迷和广泛研究的源泉。在此期间积累的数据提供了有关AKR震源区域、波的模态和极化以及震源区域内和周围存在的粒子分布的信息。人们普遍认为，由于AKR的辐射功率比热辐射高几个数量级，因此AKR的来源是等离子体不稳定性。基于损耗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一些观测到的AKR特性。因此，一般认为ECMI是AKR的来源。然而，传统的ECMI分析未能对AKR的一些与观测一致的重要特征提供清晰的解释。所提出的工作旨在理解和解释尚未从理论上理解的具体现象。强电离层-磁层耦合的一个特征是在过去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大量离子起源于电离层。在电离层中，观察到离子在与地磁场横向的方向上加速。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中起着重要作用。本文提出的研究是利用非线性动力学和网随机的概念来理解离子在低混合波包下的加速；O+的尾加热和H+的体加热；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.