| DOI: | 10.2172/1182626
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| 报告号: | LA-UR--15-23878
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| 报告题名: | DREAM3D simulations of inner-belt dynamics |
| 作者: | Cunningham, Gregory Scott
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| 出版年: | 2015
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| 发表日期: | 2015-05-26
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| 总页数: | 19
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| 国家: | 美国
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| 语种: | 英语
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| 英文关键词: | Heliospheric and Magnetospheric Physics
; radiation belts, equilibrium distribution
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| 中文主题词: | 大气科学
; 散射
; 扩散
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| 主题词: | ATMOSPHERE
; SCATTERING
; DIFFUSION
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| 英文摘要: | A 1973 paper by Lyons and Thorne explains the two-belt structure for electrons in the inner magnetosphere as a balance between inward radial diffusion and loss to the atmosphere, where the loss to the atmosphere is enabled by pitch-angle scattering from Coulomb and wave-particle interactions. In the 1973 paper, equilibrium solutions to a decoupled set of 1D radial diffusion equations, one for each value of the first invariant of motion, Îź, were computed to produce the equilibrium two-belt structure. Each 1D radial diffusion equation incorporated an L-and Îź-dependent `lifetime' due to the Coulomb and wave-particle interactions. This decoupling of the problem is appropriate under the assumption that radial diffusion is slow in comparison to pitch-angle scattering. However, for some values of Îź and L the lifetime associated with pitch-angle scattering is comparable to the timescale associated with radial diffusion, suggesting that the true equilibrium solutions might reflect `coupled modes' involving pitch-angle scattering and radial diffusion and thus requiring a 3D diffusion model. In the work we show here, we have computed the equilibrium solutions using our 3D diffusion model, DREAM3D, that allows for such coupling. We find that the 3D equilibrium solutions are quite similar to the solutions shown in the 1973 paper when we use the same physical models for radial diffusion and pitch-angle scattering from hiss. However, we show that the equilibrium solutions are quite sensitive to various aspects of the physics model employed in the 1973 paper that can be improved, suggesting that additional work needs to be done to understand the two-belt structure. |
| URL: | http://www.osti.gov/scitech/servlets/purl/1182626
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| Citation statistics: |
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| 资源类型: | 研究报告
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/41862
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| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
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| 1182626.pdf（833KB） | 研究报告 | -- | 开放获取 | | View
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| Recommended Citation: | |
Cunningham, Gregory Scott. DREAM3D simulations of inner-belt dynamics. 2015-01-01.
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