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

极光千米辐射和电离层磁层等离子体中离子的横向加速度

• 批准号: 9424282
• 负责人: Abraham Bers
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-15 至 1999-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9424282&HistoricalAwards=false
• 关键词: Auroral; Kilometric; Radiation; Transverse; Acceleration

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.

该提案的目的是解释极光千米辐射（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，这些电离层离子最终填充地球磁层并导致强烈的电离层-磁层耦合。 分析和计算技术，将被用来实现这一建议的目标，包括在等离子体中的不稳定性的时空演化，和波诱导的离子动力学混沌，包括网络随机性的新概念。 近二十年来，AKR一直是一个令人着迷和广泛研究的来源，无论是在观测上还是在理论上。 在此期间积累的数据提供了有关AKR源区，波的模式和偏振以及源区及其周围存在的粒子分布的信息。 一般认为，由于AKR的辐射功率比热辐射高出几个数量级，因此AKR的来源是等离子体不稳定性。 基于由损失锥电子分布引起的电子回旋脉塞不稳定性（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分析未能提供一个明确的解释，一些重要的特点，AKR是与观测一致。 拟议的工作旨在理解和解释理论上尚未理解的具体现象。 电离层-磁层强耦合的一个标志是过去15年来报告的一系列观测结果，这些观测结果表明磁层等离子体中的大量离子都来自电离层。 在电离层中，观察到离子在与地磁场垂直的方向上被加速。 离子间的相互作用 等离子体波似乎存在于TAI发生的区域，被认为在TAI中起重要作用。 拟议的研究是使用非线性动力学和网络随机性的概念来理解低混合波包对离子的加速;观察到的O+的尾部加热和H+的体加热;在TAI期间观察到的离子分布函数。