Roles of electrons and ions in formation of the current in mirror mode structures in the terrestrial plasma sheet: MMS observations

2020 ◽  
Author(s):  
Guoqiang Wang ◽  
Tielong Zhang ◽  
Mingyu Wu ◽  
Daniel Schmid ◽  
Yufei Hao ◽  
...  
Keyword(s):  
Plasma Sheet ◽  
Electron Velocity ◽  
Collective Behaviors ◽  
Ion Drift ◽  
Magnetospheric Multiscale ◽  
Electrons And Ions ◽  
Current Densities ◽  
Mirror Mode ◽  
Magnetospheric Multiscale Mission ◽  
The Magnetic Field

<p>Currents are believed to exist in mirror mode structures and to be self-consistent with the magnetic field depression. Here, we investigate a train of mirror mode structures in the terrestrial plasma sheet on 11 August 2017 measured by the Magnetospheric Multiscale mission. We find that bipolar current densities exist in the cross-section of two hole-like mirror mode structures, referred to as magnetic dips. The bipolar current in the magnetic dip with a size of ~2.2 ρ<sub>i</sub> (the ion gyro radius) is mainly contributed by variations of the electron velocity, which is mainly formed by the magnetic gradient-curvature drift. For another magnetic dip with a size of ~6.6 ρ<sub>i</sub>, the bipolar current is mainly caused by an ion bipolar velocity, which can be explained by the collective behaviors of the ion drift motions. These observations suggest that the electrons and ions play different roles in the formation of currents in magnetic dips with different sizes.</p>

scholarly journals Roles of electrons and ions in formation of the current in mirror-mode structures in the terrestrial plasma sheet: Magnetospheric Multiscale observations

2020 ◽  
Vol 38 (2) ◽  
pp. 309-318 ◽  
Author(s):  
Guoqiang Wang ◽  
Tielong Zhang ◽  
Mingyu Wu ◽  
Daniel Schmid ◽  
Yufei Hao ◽  
...  
Keyword(s):  
Current Density ◽  
Plasma Sheet ◽  
Electron Velocity ◽  
Collective Behaviors ◽  
Ion Drift ◽  
Magnetospheric Multiscale ◽  
Electrons And Ions ◽  
Current Densities ◽  
Mirror Mode ◽  
Magnetospheric Multiscale Mission

Abstract. Mirror-mode structures widely exist in various space plasma environments. Here, we investigate a train of mirror-mode structures in the terrestrial plasma sheet on 11 August 2017 based on the Magnetospheric Multiscale mission. We find that bipolar current densities exist in the cross section of two hole-like mirror-mode structures, referred to as magnetic dips. The bipolar current density in the magnetic dip with a size of ∼2.2 ρi (the ion gyro radius) is mainly contributed by variations of the electron velocity, which is mainly formed by the magnetic gradient–curvature drift. For another magnetic dip with a size of ∼6.6 ρi, the bipolar current density is mainly caused by an ion bipolar velocity, which can be explained by the collective behaviors of the ion drift motions. The current density inside the mirror dip contributes to the maintenance of the hole-like structure's stable. Our observations suggest that the electrons and ions play different roles in the formation of currents in magnetic dips with different sizes.

scholarly journals Roles of electrons and ions in formation of the current in mirror mode structures in the terrestrial plasma sheet: MMS observations

2019 ◽  
Author(s):  
Guoqiang Wang ◽  
Tielong Zhang ◽  
Mingyu Wu ◽  
Daniel Schmid ◽  
Yufei Hao ◽  
...  
Keyword(s):  
Cross Section ◽  
Plasma Sheet ◽  
Magnetic Gradient ◽  
Magnetospheric Multiscale ◽  
Electrons And Ions ◽  
Self Consistent ◽  
Mirror Mode ◽  
Magnetospheric Multiscale Mission ◽  
Diamagnetic Drift ◽  
The Magnetic Field

Abstract. Currents are believed to exist in mirror mode structures and to be self-consistent with the magnetic field depression. Here, we investigate a train of mirror mode structures in the terrestrial plasma sheet on 11 August 2017 measured by the Magnetospheric Multiscale mission data. We find that a bipolar current exists in the cross-section of two hole-like mirror mode structures, referred to as magnetic dips. The bipolar current in the magnetic dip with a size of ~ 3 ρi (the ion gyro radius) is mainly contributed by an electron bipolar velocity, which is mainly formed by the magnetic gradient-curvature drift. For another magnetic dip with a size of ~ 6.67 ρi, the bipolar current is mainly caused by an ion bipolar velocity, which can be explained by the ion diamagnetic drift. These observations suggest that the electrons and ions play different roles in the formation of currents in magnetic dips with different sizes.

scholarly journals The Properties of Lion Roars and Electron Dynamics in Mirror Mode Waves Observed by the Magnetospheric MultiScale Mission

2018 ◽  
Vol 123 (1) ◽  
pp. 93-103 ◽  
Author(s):  
H. Breuillard ◽  
O. Le Contel ◽  
T. Chust ◽  
M. Berthomier ◽  
A. Retino ◽  
...  
Keyword(s):  
Electron Dynamics ◽  
Magnetospheric Multiscale ◽  
Mirror Mode ◽  
Magnetospheric Multiscale Mission

scholarly journals Observational Evidence of Magnetic Reconnection in the Terrestrial Foreshock Region

2021 ◽  
Vol 922 (1) ◽  
pp. 56
Author(s):  
K. Jiang ◽  
S. Y. Huang ◽  
H. S. Fu ◽  
Z. G. Yuan ◽  
X. H. Deng ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Direct Evidence ◽  
Bow Shock ◽  
Shock Acceleration ◽  
Diffusive Shock Acceleration ◽  
Strong Energy ◽  
Magnetospheric Multiscale ◽  
Electron Distributions ◽  
Magnetospheric Multiscale Mission ◽  
The Magnetic Field

Abstract Electron heating/acceleration in the foreshock, by which electrons may be energized beyond thermal energies prior to encountering the bow shock, is very important for the bow shock dynamics. And then these electrons would be more easily injected into a process like diffusive shock acceleration. Many mechanisms have been proposed to explain electrons heating/acceleration in the foreshock. Magnetic reconnection is one possible candidate. Taking advantage of the Magnetospheric Multiscale mission, we present two magnetic reconnection events in the dawnside and duskside ion foreshock region, respectively. Super-Alfvénic electron outflow, demagnetization of the electrons and the ions, and crescent electron distributions in the plane perpendicular to the magnetic field are observed in the sub-ion-scale current sheets. Moreover, strong energy conversion from the fields to the plasmas and significant electron temperature enhancement are observed. Our observations provide direct evidence that magnetic reconnection could occur in the foreshock region and heat/accelerate the electrons therein.

scholarly journals Statistical study of linear magnetic hole structures near Earth

2021 ◽  
Vol 39 (1) ◽  
pp. 239-253
Author(s):  
Martin Volwerk ◽  
David Mautner ◽  
Cyril Simon Wedlund ◽  
Charlotte Goetz ◽  
Ferdinand Plaschke ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Occurrence Rate ◽  
Ion Temperature ◽  
Pressure Balance ◽  
Magnetospheric Multiscale ◽  
Background Magnetic Field ◽  
Earth’S Bow Shock ◽  
Mirror Mode ◽  
Magnetospheric Multiscale Mission ◽  
Upstream Solar Wind

Abstract. The Magnetospheric Multiscale mission (MMS1) data for 8 months in the winter periods of 2017–2018 and 2018–2019, when MMS had its apogee in the upstream solar wind of the Earth's bow shock, are used to study linear magnetic holes (LMHs). These LMHs are characterized by a magnetic depression of more than 50 % and a rotation of the background magnetic field of less then 10∘. A total of 406 LMHs are found and, based on their magnetoplasma characteristics, are split into three categories: cold (increase in density, little change in ion temperature), hot (increase in ion temperature, decrease in density) and sign change (at least one magnetic field component changes sign). The occurrence rate of LMHs is 2.3 per day. All LMHs are basically in pressure balance with the ambient plasma. Most of the linear magnetic holes are found in ambient plasmas that are stable against the mirror-mode generation, but only half of the holes are mirror-mode-stable inside.

Intercomponent Momentum Transport and Electrical Conductivity of Collisionless Plasma

1973 ◽  
Vol 51 (24) ◽  
pp. 2604-2611 ◽  
Author(s):  
H. E. Wilhelm
Keyword(s):  
Electrical Conductivity ◽  
Electric Field ◽  
Collisionless Plasma ◽  
Electrical Current ◽  
Distribution Functions ◽  
Momentum Transport ◽  
Ion Drift ◽  
Moment Approximation ◽  
Electrons And Ions ◽  
Two Component

Based on the Lenard–Balescu equation, the interaction integral for the intercomponent momentum transfer in a two-component, collisionless plasma is evaluated in closed form. The distribution functions of the electrons and ions are represented in the form of nonisothermal, displaced Max wellians corresponding to the 5-moment approximation. As an application, the transport of electrical current in an electric field is discussed for infrasonic up to sonic electron–ion drift velocities.

scholarly journals The geometric factor of electrostatic plasma analyzers: A case study from the Fast Plasma Investigation for the Magnetospheric Multiscale mission

2012 ◽  
Vol 83 (3) ◽  
pp. 033303 ◽  
Author(s):  
Glyn A. Collinson ◽  
John C. Dorelli ◽  
Levon A. Avanov ◽  
Gethyn R. Lewis ◽  
Thomas E. Moore ◽  
...  
Keyword(s):  
Geometric Factor ◽  
Magnetospheric Multiscale ◽  
Magnetospheric Multiscale Mission ◽  
Plasma Investigation

BALLISTIC COLLECTION TRANSISTORS AND THEIR APPLICATIONS

1994 ◽  
Vol 05 (03) ◽  
pp. 349-379 ◽  
Author(s):  
T. ISHIBASHI ◽  
Y. YAMAUCHI ◽  
E. SANO ◽  
H. NAKAJIMA ◽  
Y. MATSUOKA
Keyword(s):  
Integrated Circuits ◽  
High Speed ◽  
Monte Carlo Analysis ◽  
Heterojunction Bipolar Transistor ◽  
Doping Profile ◽  
Electron Velocity ◽  
Collector Current ◽  
Microwave Characterization ◽  
Current Densities ◽  
Dynamic Frequency

We describe the design, fabrication and application of ballistic collection transistors (BCTs) in which electron velocity overshoot is introduced in the collector of a GaAs-based heterojunction bipolar transistor. The guideline for the BCT design is the effective confinement of electrons to the Γ-valley, as simulated by Monte Carlo analysis, and the control of electron energy is accomplished basically with an i-p+-n+ doping profile. Microwave characterization demonstrates the existence of significant overshoot and cutoff frequencies higher than 100 GHz at collector current densities in the mid 104 A/cm 2 range for a typical BCT structure. Some high speed integrated circuits implemented with BCTs include a selector circuit that operates at bit rates up to 40 Gb/s, a dynamic frequency divider with divide-by-four function up to 50 GHz and a broadband preamplifier having an S21 bandwidth as high as 40 GHz.

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