地球磁层顶的漂移动力学Alfven波不稳定性及其反常输运效应

	地球磁层顶的漂移动力学Alfven波不稳定性及其反常输运效应
	濮祖荫 ; 傅绥燕 ; 郭世宠 ; 刘振兴
刊名	地球物理学报
	1991
卷号	34 期号:4 页码:404-414
关键词	磁层顶漂移动力学不稳定性反常输运
ISSN号	0001-5733
其他题名	UNSTABLE DRIFT KINETIC ALFVEN MODEL AT THE MAGNETOPAUSE
通讯作者	北京8701信箱
中文摘要	本文用回旋动力学研究了磁层顶等离子体低频漂移动力学不稳定性.在β≥1附近发现两支不稳定的漂移动力学Alfvèn模(DKA).它们可在▽T(∥-▽n)(?)0时激发,速度剪切提供主要的自由能源.两支DKA均具有非零的(δE_y,δE_∥)和(δB_x,δB_∥).在湍动的非线性饱和状态下,δB_x的起伏可导致很强的反常输运,当\|δB_x\|=1nT时,D_⊥可达到10~9m~2/s的数量级.因此,DKA可能在太阳风-磁层耦合过程中起重要作用.
英文摘要	Low frequency drift kinetic instabilities at the magnetopause are investigated by using the gyrokinetic formalism- Two unstable branches of drift kinetic Alfven modes, A and B, may appear in the case of plasma β≈1, which are shown to be related with inhomogenities of ions and electrons, respectively. The velocity shear provides an important free energy source. The presence of the temperature gradient anti-parallel to the density gradient is necessary for exciting the instabilities. It is found that for both A and B modes the magnetic field has perturbations in the direction normal to the magnetopause. Once the amplitude of waves grows and the perturbation becomes turbulent, magnetic migration may take place, leading to substantial anomalous transport across the magnetopause. Quasilinear anomalous diffusivity is calculated and shown to be in the order of 10'm'/s even if \|δB_x\|=1nT. Thus, the drift Kinetic Alfven mode can be considered to be responsible for most of the anomalous transport phenomena in the case of northward 1MF
学科主题	空间物理
资助信息	国家自然科学基金
语种	中文
内容类型	期刊论文
源URL	[http://ir.cssar.ac.cn/handle/122/1194]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	濮祖荫,傅绥燕,郭世宠,等. 地球磁层顶的漂移动力学Alfven波不稳定性及其反常输运效应[J]. 地球物理学报,1991,34(4):404-414.
APA	濮祖荫,傅绥燕,郭世宠,&刘振兴.(1991).地球磁层顶的漂移动力学Alfven波不稳定性及其反常输运效应.地球物理学报,34(4),404-414.
MLA	濮祖荫,et al."地球磁层顶的漂移动力学Alfven波不稳定性及其反常输运效应".地球物理学报 34.4(1991):404-414.