Study of Cross Polar Cap Potential Behavior During Storms and Superstorms Using Defense Meteorological Satellite Program (DMSP) Data

使用国防气象卫星计划 (DMSP) 数据研究风暴和超级风暴期间跨极冠潜在行为

• 批准号: 0637791
• 负责人: Marc Hairston
• 金额: $ 21.5万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-01 至 2010-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0637791&HistoricalAwards=false
• 关键词: Study; Cross; Polar; Cap; Potential

One of the key features in the coupling of the solar wind to the magnetosphere and the magnetosphere to the ionosphere coupling is the electric potential drop imposed across the polar cap. This potential drop and its associated potential distribution pattern in the polar ionosphere serves as a proxy measurement of the coupling between the solar wind and the magnetosphere. Recent work has shown that the polar ionosphere behaves differently under the extreme solar wind conditions that produce the very large magnetic storms known as superstorms as compared with the behavior during quiet times and moderate magnetic storms. It appears that the polar cap potential drop saturates at a set level no matter how strong the system is driven by the electric field carried by the solar wind. In addition the size of the polar cap itself appears to stop expanding under these saturated potential conditions. Understanding the behavior of the polar cap potential and the size of the polar cap itself and how they respond to solar wind drivers (the solar wind electric field and the solar wind ram pressure) as well as to the changes in the conductivity in the ionosphere are key to understanding the underlying physics of the phenomenon and in developing accurate and reliable models of the geospace environment. This three-year project will use the database of polar ionospheric parameters from the DMSP spacecraft to explore the polar ionosphere's response to regular storms and to the extreme superstorms. The project will develop an empirical model of the size of the polar cap as a function of the magnitude of the polar cap potential and various solar wind inputs. Periods of medium to high values of the solar wind electric field will be examined to determine the transition region where the saturation of the potential begins to appear. The project will also compare the ionospheric Pedersen conductivity derived from the Hill-Siscoe model with the value derived using the AMIE

太阳风与磁层和电离层耦合磁层偶联的关键特征之一是在极盖上施加的电势下降。 这种潜在的跌落及其相关的电势分布模式在极性电离层中是对太阳风与磁层之间耦合的代理测量。最近的工作表明，与在安静的时期和中等磁场中的行为相比，极端的太阳风条件下极地电离层的行为不同。 看来，无论系统由太阳风带来的电场驱动，极性盖电势下降在设定水平上饱和。此外，在这些饱和电势条件下，极性盖本身的尺寸似乎停止扩展。了解极性盖电位的行为和极性盖本身的大小以及它们如何对太阳风驱动器（太阳能电场和太阳能风电场压力）以及电离层电导率的变化是了解现象的基础物理学以及在Geepace环境的准确和可靠的模型中的关键。这个为期三年的项目将使用来自DMSP航天器的极地电离层参数的数据库来探索极地离子层对常规风暴和极端超级风暴的反应。 该项目将开发出极大帽的大小的经验模型，这是极盖电势和各种太阳风输入的幅度的函数。将检查中等至高值的中等值的周期，以确定电势开始出现的过渡区域。该项目还将比较使用AMIE得出的值的电离层PEDERSEN电导率