DREAM3D simulations of inner-belt dynamics

doi:10.2172/1182626

GSTDTAP > 地球科学

DOI	10.2172/1182626
报告编号	LA-UR--15-23878
来源ID	OSTI ID: 1182626
	DREAM3D simulations of inner-belt dynamics
	Cunningham, Gregory Scott
	2015-05-26
出版年	2015
页数	19
语种	英语
国家	美国
领域	地球科学
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.
英文关键词	Heliospheric and Magnetospheric Physics radiation belts, equilibrium distribution
URL	查看原文
来源平台	US Department of Energy (DOE)
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/6868
专题	地球科学
推荐引用方式 GB/T 7714	Cunningham, Gregory Scott. DREAM3D simulations of inner-belt dynamics,2015.