Coupling of Micro- and Meso-Scale Processes During Early Stage Plasmaspheric Refilling

早期血浆球再充填期间微观和介观尺度过程的耦合

• 批准号: 9529623
• 负责人: Nagendra Singh
• 金额: $ 13.84万
• 依托单位: University of Alabama in Huntsville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9529623&HistoricalAwards=false
• 关键词: Coupling; Micro; Meso; Scale; Processes

This study addresses the problem of ion-beam driven waves and their effects on the accumulation of ionospheric plasma in the outer plasmasphere. This addresses a major problem in magnetospheric physics, that is, the refilling of the plasmasphere following geomagnetic storms. The primary goal of the project is to firmly establish the methodology of the following basic paradigm and modeling approach assumes that as soon as the plasma flow parameters cross marginal stability conditions for the waves, the instabilities are triggered and clamp the flow near the conditions for marginal stability. Thus, from the waves and instability standpoint, the quasisteady state of the plasma is known a priori. When the macroscopic processes drive the plasma away form this state toward instability, we know the excess momentum and the directed kinetic energy which need to be thermalized by the instability process. This facilitates an easy calculation of the anomalous plasma transport coefficients to be included in a mesoscale model based on plasma transport equations without knowing the details of the instabilityprocess. This approach is termed the Anomalous Plasma Effects or APE model. The research strategy consists of 1) systematic determination of easy-to-use semiempirical relations for the marginal stability conditions for the plasma during the refilling situation, 2) small-scale particle- in-cell simulations to characterize plasma heating by the instabilities and to test the APE model, and 3) mesoscale modeling using two-stream hydrodynamic code including the anomalous transport coefficients.

本研究探讨了离子束驱动波的问题及其对外层等离子体积累的影响。 这解决了磁层物理学中的一个主要问题，即磁暴后等离子体的重新填充。 该项目的主要目标是牢固地建立以下基本范例和建模方法的方法论，假设一旦等离子体流参数越过波的边缘稳定性条件，就触发不稳定性并将流钳制在边缘稳定性条件附近。 因此，从波动和不稳定性的观点来看，等离子体的准稳态是先验已知的。 当宏观过程驱使等离子体远离这种状态而走向不稳定时，我们知道不稳定过程需要热化的多余动量和定向动能。 这使得在不知道不稳定过程细节的情况下，基于等离子体输运方程的中尺度模型中可以很容易地计算出反常等离子体输运系数。 这种方法被称为异常等离子体效应或APE模型。 研究策略包括：1）系统地确定易于使用的半经验关系的边缘稳定性条件的等离子体在再填充的情况下，2）小规模的粒子在细胞模拟来表征等离子体加热的不稳定性和测试的APE模型，和3）中尺度模拟使用双流流体动力学代码，包括异常传输系数。