Magnetosphere - Ionosphere Coupling During Periods of Extreme Solar Wind Driving

太阳风、磁层和电离层系统的动力学是由太阳风电场驱动的。在正常太阳风条件下，交叉极地帽势(CPCP)差随太阳风电场的变化而变化。然而，在极端的太阳风条件下，例如发生在磁暴期间的情况，CPCP变得非线性并饱和。这项研究将主要支持弗吉尼亚理工大学和州立大学的一名博士后学者，他将被教授相干和非相干散射电离层雷达的操作。本研究的目标是调查饱和的原因，并了解为什么南北半球的行为不同。对CPCP饱和有两种解释。在一个日侧区域1，场向电流限制了强驱动的磁重联率，在另一个区域，由于太阳风的AlfvéNic电导和电离层的Pedersen电导之间的电导不匹配，太阳风建立的电场的一部分在电离层反射。该团队提出了第三种解释，即电离层等离子体不稳定导致电离层电流受到限制，并反馈到磁层。这项研究涉及使用混合模拟代码和来自SuperDARN和ISR雷达在电离层的观测、ACE太阳风观测和磁层THEMIS数据。

The dynamics of the solar wind, magnetosphere and ionosphere system are driven by the solar wind electric field. Under normal solar wind conditions the cross polar cap potential (CPCP) difference scales with the solar wind electric field. However under extreme solar wind conditions such as those occurring during magnetic storms the CPCP becomes non-linear and saturates. This study will primarily support a post-doctoral scholar at Virginia Polytechnic and State University who will be taught about the operation of both coherent and incoherent scatter ionospheric radars.The goals of this study are to investigate the causes of the saturation and to understand why the northern and southern hemispheres behave differently. There have been two classes of explanations for CPCP saturation. In one dayside region 1 field aligned currents limit the magnetic reconnection rate for strong driving and in the other an Alfvén wing is set up in which a portion of the electric field set up by the solar wind is reflected at the ionosphere as the result of a conductance mismatch between the Alfvénic conductance of the solar wind and the Pedersen conductance of the ionosphere. The team proposes a third explanation that ionospheric plasma instabilities lead to limitations on ionospheric currents and that this feeds back into the magnetosphere. The research involves using a hybrid simulation code and observations from SuperDARN and ISR radar in the ionosphere, ACE solar wind observations and THEMIS data in the magnetosphere.