| 项目编号: | 1536738
|
| 项目名称: | Turbulent Ion Heating in the Magnetosheath |
| 作者: | Christopher Chaston
|
| 承担单位: | University of California-Berkeley
|
| 批准年: | 2016
|
| 开始日期: | 2016-05-15
|
| 结束日期: | 2019-04-30
|
| 资助金额: | 281023
|
| 资助来源: | US-NSF
|
| 项目类别: | Continuing grant
|
| 国家: | US
|
| 语种: | 英语
|
| 特色学科分类: | Geosciences - Atmospheric and Geospace Sciences
|
| 英文关键词: | ion
; heating process
; magnetosheath
; solar wind
; magnetosphere
; magnetosheath ion
; additional instability
; magnetic field
; wave/ion heating event
; initial condition
; turbulence
; secondary wave emission
; sheath region
; ion distribution
; simulation result
; magnetosheath plasma
; ion heating
|
| 英文摘要: | Earth's magnetic field encloses it in a protective cocoon, called the magnetosphere, deflecting most of the solar wind around it. The solar wind is a stream of charged particles, approximately equal numbers of ions and electrons, and magnetic fields blowing outward from the Sun, which varies in intensity with solar activity. The solar wind moves so fast that when it encounters the magnetosphere a shock forms upstream from it. As solar wind plasma passes through the shock it is slowed down and then flows around the magnetosphere in a sheath region, called the magnetosheath. In this region the magnetic field is erratic or turbulent and evidence suggests that magnetosheath ions are heated as this turbulence is dissipated. The topic is compelling because the potential importance of turbulence and associated ion heating has only recently been recognized. Ions in the magnetosheath eventually cross the magnetopause to provide the dominant source of magnetospheric plasmas, thus changes in their temperature and other properties can have a profound effect on the stability of the magnetosphere itself, which can lead to explosive releases of energy during geomagnetic storms and substorms. The methodology for this study is creative and an important advance over previous studies because it is the first self-consistent comprehensive treatment of this turbulence and its dissipation. As such, the potential for new discoveries is high. Advances in understanding will have benefit to society because, in the longer term, they will contribute to the development of an improved predictive capability that can be used to minimize the impacts of such events. This research contributes to the development of a scientific workforce by training a postdoctoral student and a graduate student. Research results will be disseminated through publications, conferences, and community outreach.
In order to fulfill its objectives, this study investigate how Alfvenic turbulence heats magnetosheath ions, how the heating process saturates, the rate at which energy is transferred to the ions, how electromagnetic energy is transported to support the heating process, how secondary wave emissions develop during the heating, and how the heating process influences the bulk characteristics of the magnetosheath plasma. The primary tool is a 3D hybrid particle in cell model. The proposal uses wave/ion heating events observed by the THEMIS satellites to both specify initial conditions and to validate simulation results. An innovative aspect is the coupled treatment of both the cascade processes associated with plasma turbulence and the additional instabilities that arise from the anisotropies that develop in the ion distributions. |
| 资源类型: | 项目
|
| 标识符: | http://119.78.100.158/handle/2HF3EXSE/92380
|
| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
|
|
There are no files associated with this item.
|
| Recommended Citation: | |
Christopher Chaston. Turbulent Ion Heating in the Magnetosheath. 2016-01-01.
|
|
|