ISEE observations of low-latitude boundary layer for northward interplanetary magnetic field: Implications for cusp reconnection

1996 ◽  
Vol 101 (A12) ◽  
pp. 27239-27249 ◽  
Author(s):  
G. Le ◽  
C. T. Russell ◽  
J. T. Gosling ◽  
M. F. Thomsen
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Interplanetary Magnetic Field ◽  
Low Latitude ◽  
Low Latitude Boundary Layer

scholarly journals Plasma transport into the duskside magnetopause caused by Kelvin–Helmholtz vortices in response to the northward turning of the interplanetary magnetic field observed by THEMIS

2019 ◽  
Author(s):  
Guang Qing Yan ◽  
George K. Parks ◽  
Chun Lin Cai ◽  
Tao Chen ◽  
James P. McFadden ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Interplanetary Magnetic Field ◽  
Time History ◽  
Plasma Transport ◽  
Low Latitude ◽  
Unique Event ◽  
History Of ◽  
The Magnetic Field ◽  
Low Latitude Boundary Layer

Abstract. A train of Kelvin–Helmholtz (K–H) vortices with plasma transport across the magnetopause has been observed by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) when the interplanetary magnetic field (IMF) abruptly turns northward. This unique event occurred without pre-existing denser boundary layer to facilitate the instability. Two THEMIS spacecraft, TH-A and TH-E, separated by 3 Re, periodically encountered the duskside magnetopause and the low-latitude boundary layer (LLBL) with a period of 2 minutes and tailward propagation of 194 km/s. There was no high-velocity low-density feature, but the rotations in the bulk velocity observation, distorted magnetopause with plasma parameter fluctuations and the magnetic field line stretching, indicate the formation of rolled-up K–H vortices at the duskside magnetopause. A mixture of magnetosheath ions with magnetospheric ions and enhanced energy flux of hot electrons is identified in the K–H vortices. This mixture region appears more periodic at the upstream spacecraft and more dispersive at the downstream location, indicating a significant transport can occur and evolve during the tailward propagation of the K–H waves. There is still much work to fully understand the Kelvin–Helmholtz mechanism. The observations of direct response to the northward turning of the IMF, the unambiguous plasma transport within the vortices, involving both ion and electron fluxes can provide additional clues to the K–H mechanism.

scholarly journals Region-1 field aligned currents in experiments on laser-produced plasma interacting with magnetic dipole

2010 ◽  
Vol 6 (S274) ◽  
pp. 40-43
Author(s):  
I. F. Shaikhislamov ◽  
Yu. P. Zakharov ◽  
V. G. Posukh ◽  
E. L. Boyarintsev ◽  
A. V. Melekhov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Solar Wind ◽  
Experimental Evidence ◽  
Magnetic Dipole ◽  
Present Report ◽  
Low Latitude ◽  
The Earth ◽  
Field Aligned Current ◽  
Low Latitude Boundary Layer

AbstractIn previous experiments by the authors a generation of intense field aligned current (FAC) system on Terrella poles was observed. In the present report a question of these currents origin in a low latitude boundary layer of magnetosphere is investigated. Experimental evidence of such a link was obtained by measurements of magnetic field generated by tangential sheared drag. Results suggest that compressional and Alfven waves are responsible for FAC generation. The study is most relevant to FAC generation in the Earth and Hermean magnetospheres following pressure jumps in Solar Wind.

Thickness of the low-latitude boundary layer at different levels of magnetic field fluctuations in the magnetosheath

2015 ◽  
Vol 55 (5) ◽  
pp. 573-581 ◽  
Author(s):  
S. S. Znatkova ◽  
E. E. Antonova ◽  
M. S. Pulinets ◽  
I. P. Kirpichev ◽  
M. O. Riazantseva
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Low Latitude ◽  
Field Fluctuations ◽  
Different Levels ◽  
Low Latitude Boundary Layer

The Viscous Magnetosphere

1996 ◽  
Author(s):  
Charles F. Kennel
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Radial Distance ◽  
Velocity Shear ◽  
Low Latitude ◽  
Viscous Interaction ◽  
Field Lines ◽  
Layer Flow ◽  
Solar Wind Origin ◽  
Low Latitude Boundary Layer

This chapter describes how the magnetosphere is shaped by the tangential shear stress exerted at the magnetopause by collisionless viscosity. In Section 4.2, we discuss the low-latitude boundary layer (LLBL), which contains plasma of solar wind origin that has been transported across the magnetopause current layer. The velocity shear in the LLBL drives field-aligned currents into the ionosphere on the morning side and out of the ionosphere on the evening side (Section 4.3). These currents are of the appropriate sense to drive two-cell convection in the highlatitude ionosphere. The footprint of the LLBL in the ionosphere to which the field aligned currents connect is clearly identifiable by its characteristic particle precipitation (Section 4.4). The shear in the LLBL also generates 1-20 mHz PC 4- 5 micropulsations whose polarizations, tailward propagation, and phase speeds are consistent with the Kelvin-Helmholtz (K-H) instability (Section 4.5). The K-H vortices may couple to “vortex auroras” in the local afternoon sector of the auroral oval (Section 4.6). Vortex auroral dissipation may be responsible for a morningevening asymmetry in the viscous interaction and its manifestations. Organized vortical flows have been observed not only next to the magnetopause, but also near the center of the plasma sheet, accompanied by local quasiperiodic magnetic field oscillations and PC 5 micropulsations on the ground (Section 4.7). In Section 4.8, we discuss observations of a thick boundary layer flow on closed field lines next to the magnetopause 220 RE downstream. This puts us in a position to estimate the rates of particle and energy injection into the magnetosphere due to the viscous interaction (Section 4.9). Spacecraft crossings of the magnetopause last from a few seconds to a few minutes and are characterized by a rapid, distinct rotation of the magnetic field and striking changes in plasma density, pressure, flow velocity, composition, and energetic particle distribution (Williams, 1979a; 1980; Williams et al., 1979). A broader boundary layer lies just inside the magnetopause. The so-called low-latitude boundary layer was first identified at 18 RE radial distance in the magnetotail using Vela 4B (Hones et al., 1972) and Vela 5 and 6 (Akasofu et al., 1973b) low-energy plasma measurements.

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