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DOI	10.1029/2020GL091613
	On the Origin of Donut-Shaped Electron Distributions Within Magnetic Cavities
	Li J.-H.; Zhou X.-Z.; Zong Q.-G.; Yang F.; Fu S.; Yao S.; Liu J.; Shi Q.
发表日期	2021
ISSN	0094-8276
卷号	48 期号:2
英文摘要	Magnetic cavities, also known as magnetic holes, are ubiquitous in space plasmas characterized by depressed magnetic strength and enhanced plasma pressure. Most of the observed cavities are associated with anisotropic particle distributions with higher fluxes in the direction perpendicular to the magnetic field. Recent observations of kinetic-scale magnetic cavities have identified another type of electron distributions in the pitch angle spectrum, the so-called donut-shaped distributions, although their formation mechanism remains unclear. Here, we present a simplistic model of cavity shrinkage and deepening, in which electrons are traced backward in time to the initial, equilibrium-state cavity. The resulting electron distributions, determined from Liouville's theorem, agree with the observations in the presence of donut-shaped pitch angle structures. The model also enables a quantitative evaluation on the roles of betatron cooling, radial transport, and pitch angle variations in the formation of donut-shaped electron distributions within evolving magnetic cavities. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	Electrons; Magnetism; Microstrip devices; Anisotropic particles; Electron distributions; Equilibrium state; Formation mechanism; Magnetic strength; Plasma pressures; Quantitative evaluation; Radial transport; Magnetoplasma
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/169186
作者单位	School of Earth and Space Sciences, Peking University, Beijing, China; Institute of Space Sciences, Shandong University, Weihai, China; Department of Physics, University of Alberta, Edmonton, Canada
推荐引用方式 GB/T 7714	Li J.-H.,Zhou X.-Z.,Zong Q.-G.,et al. On the Origin of Donut-Shaped Electron Distributions Within Magnetic Cavities[J],2021,48(2).
APA	Li J.-H..,Zhou X.-Z..,Zong Q.-G..,Yang F..,Fu S..,...&Shi Q..(2021).On the Origin of Donut-Shaped Electron Distributions Within Magnetic Cavities.Geophysical Research Letters,48(2).
MLA	Li J.-H.,et al."On the Origin of Donut-Shaped Electron Distributions Within Magnetic Cavities".Geophysical Research Letters 48.2(2021).