Understanding Conjugacy and Non-conjugacy of the Auroral Electrojet System

了解极光电喷射系统的共轭和非共轭

• 批准号: 1104338
• 负责人: Shinichi Ohtani
• 金额: $ 28.49万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1104338&HistoricalAwards=false
• 关键词: Understanding; Conjugacy; Non; conjugacy; Auroral

This project will examine the magnetic conjugacy and non-conjugacy of the auroral electrojet system. Instances of non-conjugate behavior may arise from one or more of four different reasons. The possible reasons for non-conjugate behavior are: (1) inter-hemispherical differences in Earth's internal magnetic field, (2) differences in ionospheric conductivity due to differences in solar illumination, (3) external electric currents driven by the interplanetary magnetic field (IMF) and (4) field-aligned currents flowing from one hemisphere to the other. Statistical analyses of a large number of events will be used to determine under what conditions each of the possible reasons for non-conjugate behavior are operative. The project will characterize differences and similarities in the auroral electrojet systems in the two hemispheres and will determine the dependence on season, location and IMF conditions. Most of our knowledge of the behavior of auroral phenomena comes from observations in the northern hemisphere and the common assumption is that the southern hemisphere is simply a mirror of what happens in the northern hemisphere. Two locations, one in the northern hemisphere and one in the southern hemisphere are referred to a conjugate if they are connected by a magnetic field line. Optical observations done simultaneously in both hemispheres has shown many instances of non-conjugate behavior. This project will use magnetic field measurements taken in both hemispheres from a large number of magnetometers to examine the conditions that produce non-conjugate behavior.

本项目将研究极光电喷系统的磁共轭性和非共轭性。非婚配行为的实例可能由以下四个不同原因中的一个或多个原因引起。非共轭行为的可能原因有：(1)地球内部磁场的半球间差异，(2)由于太阳光照的差异导致电离层电导率的差异，(3)由行星际磁场（IMF）驱动的外部电流和(4)从一个半球流向另一个半球的场向电流。将使用大量事件的统计分析来确定在什么条件下非共轭行为的每个可能原因是有效的。该项目将描述两个半球极光电喷射系统的异同，并将确定对季节、地点和IMF条件的依赖。我们对极光现象行为的大部分知识来自于对北半球的观察，通常的假设是南半球只是北半球发生的事情的镜像。两个位置，一个在北半球，一个在南半球，如果它们被磁力线连接，就被称为共轭。在两个半球同时进行的光学观测显示了许多非共轭行为的实例。该项目将使用大量磁力计在两个半球进行磁场测量，以检查产生非共轭行为的条件。