This is a continuation of a study based on the GEM program in 2009 where its research was originally funded for three years. This covers that last two years of that effort. The only change is the location at which the research will be carried out. The effort had two parts. One is to carry out a scientific investigation and the second is to aid in running the scientific parts of the GEM program. Both tasks are discussed below.
The plasmasphere is a region of relatively dense cold plasma (1000 cm-3) found near the Earth (~ 4 RE). This is proposal to use data analysis and simulation to investigate drainage of this cold plasma from the plasmasphere and its effect on the dynamics of the magnetosphere. Recent findings indicate that leakage of plasma from the plasmasphere may affect magnetospheric dynamics during disturbed times. This research will focus on four of the effects that have been suggested during magnetic storms. In particular the following questions will be examined: 1) Does the cold plasma affect the reconnection rate at the dayside magnetosphere? 2) Does this reduce the overall solar-wind/magnetosphere coupling? 3) Does the cold plasma influence the decay of electron radiation belts? 4) Does it lead to radiation belt dropouts and sudden recoveries? Answers to these questions should lead to a deeper understanding of the effects of cold plasma in the magnetosphere.
This research will impact future global models to magnetospheric dynamics.
The GEM program's research protocol is to concentrate on specific focus topics. Each of these lasts three years. Part of the funding for this research will be used to help coordinate two of these focus group efforts. These are the focus group on 'Plasmasphere-Magnetosphere Interactions' and the group on 'Diffuse Auroral Precipitation'.
The plasmasphere is a region of cold plasma that builds up in the Earth’s magnetosphere; the origin of the cold plasma is the evaporation upward of hydrogen atoms off the upper atmosphere. In this GEM project, the impact of the plasmasphere on the dynamics of the Earth’s magnetosphere was explored. INTELLECTUAL MERIT. Some of the scientific findings of this project are the following. (1) Ideas about how the plasmaspheric plasma can hinder the interaction of the solar wind with the Earth were solidified and furthered in this GEM project; this included quantitatively estimating the magnitude of the impact of the plasmasphere on the driving of the magnetosphere by the solar wind. (2) The plasmasphere grows substantially in size during an event called a "calm before the storm"; in this GEM project the occurrence or not of a calm before the storm was explained by the morphology of features on the Sun that are associated with the driving of geomagnetic storms at Earth. (3) The plasmasphere is the home of several types of plasma waves that are believed to interact with other particle populations of the magnetosphere, including the radiation belt; in this GEM project the scattering of radiation-belt electrons was measured as the electrons crossed plumes of plasmaspheric plasma in the dayside magnetosphere. (4) When geomagnetic activity becomes high, a plume of plasmaspheric plasma forms in the dayside magnetosphere that is universally believed to be drainage of plasmaspheric plasma that has been stored in the magnetosphere; in this GEM project the discovery and analysis of "long-lived" (weeks) plasmaspheric plumes pose a dilemma for the picture that the plumes are drainage from storage in the magnetosphere. (5) The dilemma of the long-lived drainage plumes led to computer simulations of the physics of evaporation of hydrogen from the topside atmosphere in this GEM project; modifications of the upper atmosphere that might partially explain the origin of the plasma in long-lived plumes were suggested. BROADER IMPACTS. Funding from this GEM project enabled the Principal Investigator to participate in the Los Alamos Space Weather Summer School at Los Alamos National Laboratory where his research investigations have been used to create student research projects. Funding from this project also enabled the Principal Investigator to attend the NSF GEM Summer Meetings and to serve as the GEM-SHINE Liaison.
