EMHD theory and observations of electron solitary waves in magnetotail plasmas

Ji, X. F.; Wang, Xiaogang; Sun, W.; Xiao, Chijie; Shi, Quanqi; Liu, Jiang; Pu, Z. Y.

doi:10.1002/2014ja019924

Cited by 54 publications

(77 citation statements)

References 26 publications

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“…These include the electron mirror mode or field-swelling instability (Gary & Karimabadi, 2006;Pokhotelov et al, 2013), solitary waves (Ji et al, 2014;Li et al, 2016;Stasiewicz et al, 2003;Yao et al, 2017), decaying turbulence (Haynes et al, 2015;Huang, Du, et al, 2017;Roytershteyn et al, 2015), and electron Kelvin-Helmholtz instability (Pritchett & Mozer, 2009). These include the electron mirror mode or field-swelling instability (Gary & Karimabadi, 2006;Pokhotelov et al, 2013), solitary waves (Ji et al, 2014;Li et al, 2016;Stasiewicz et al, 2003;Yao et al, 2017), decaying turbulence (Haynes et al, 2015;Huang, Du, et al, 2017;Roytershteyn et al, 2015), and electron Kelvin-Helmholtz instability (Pritchett & Mozer, 2009).…”

Section: 1029/2019gl082637mentioning

confidence: 99%

“…This means that this MH was on a boundary layer with temperature gradient. The Biermann battery effect ∇n e × ∇ T e might be significant to generate electron solitary waves (Ji et al, 2014;Li et al, 2016), which possibly provided the seed depression for the MH. The Biermann battery effect ∇n e × ∇ T e might be significant to generate electron solitary waves (Ji et al, 2014;Li et al, 2016), which possibly provided the seed depression for the MH.…”

Section: 1029/2019gl082637mentioning

confidence: 99%

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Observations of a Kinetic‐Scale Magnetic Hole in a Reconnection Diffusion Region

Zhong

Zhou

Huang

et al. 2019

Geophysical Research Letters

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Magnetic holes have been widely observed in various space plasma systems. The origin of magnetic holes and their influence to background plasma are under debate. In this paper, we show a kinetic‐scale electron vortex magnetic hole in a nonideal region of an active X line, which was observed by the Magnetospheric Multiscale mission at the dayside magnetopause. Intense current and nonideal electric field in the electron frame were observed within the magnetic hole, which led to a strong energy dissipation. Thus, the electron vortex magnetic hole probably provided an additional energy dissipation channel besides the electron diffusion region adjacent to the hole. We suggest that magnetic reconnection provided favorable conditions for the formation of this kinetic‐scale magnetic hole and is an important source of magnetic holes in space plasma.

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Section: 1029/2019gl082637mentioning

confidence: 99%

Section: 1029/2019gl082637mentioning

confidence: 99%

Observations of a Kinetic‐Scale Magnetic Hole in a Reconnection Diffusion Region

Zhong

Zhou

Huang

et al. 2019

Geophysical Research Letters

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“…In some ways this instability is analogous to the mirror instability. A fluid approach based on electron-MHD has shown that soliton waves can be formed from the electron magnetosonic wave mode, 22 providing a way to form one-dimensional electron-scale magnetic structures.…”

Section: Introductionmentioning

confidence: 99%

Electron vortex magnetic holes: A nonlinear coherent plasma structure

et al. 2015

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We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to electron mass ratio. These structures, electron vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped electrons in petal-like orbits. The trapped electron population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the plasma, and are stable over at least 100 electron gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform plasma. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial plasma sheet. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical plasmas. V C 2015 AIP Publishing LLC.

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“…Alternative explanations have also been proposed by Balikhin et al [] and Ji et al []. In a second assessment of the Ge et al observations, Balikhin et al [] investigated the Time History of Events and Macroscale Interactions during Substorms (THEMIS) data in more detail.…”

Section: Introductionmentioning

confidence: 99%

“…Ji et al [] instead explained the formation in terms of electron solitary waves. These are propagating structures similar to the slow magnetosonic solitons observed in the magnetosheath and the solar wind [e.g., Baumgärtel , ; Baumgärtel et al , ; Stasiewicz et al , ; Stasiewicz , ] but driven and maintained by electron‐scale physics, in particular the electric and magnetic fields generated by the Biermann battery effect.…”

Section: Introductionmentioning

confidence: 99%

Properties and origin of subproton‐scale magnetic holes in the terrestrial plasma sheet

2015

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Electron-scale magnetic depressions in the terrestrial plasma sheet are studied using Cluster multispacecraft data. The structures, which have an observed duration of~5-10 s, are approximately 200-300 km wide in the direction of propagation, and they show an average reduction in the background magnetic field of 10-20%. A majority of the events are also associated with an increase in the high-energy high pitch angle electron flux, which indicates that the depressions are presumably generated by electrons with relatively high velocity perpendicular to the background magnetic field. Differences in the recorded electron spectra in the four spacecraft indicates a possible nongyrotropic structure. Multispacecraft measurements show that a subset of events are cylindrical, elongated along the magnetic field, and with a field-parallel scale size of at a minimum 500 km. Other events seem to be better described as electron-scale sheets, about 200-300 km thick. We find that no single formation mechanism can explain this variety of events observed. Instead, several processes may be operating in the plasma sheet, giving rise to similar magnetic field structures in the single-spacecraft data, but with different 3-D structuring. The cylindrical structures have several traits that are in agreement with the electron vortex magnetic holes observed in 2-D particle-in-cell simulations of turbulent relaxation, whereas the sheets, which show nearly identical signatures in the multispacecraft data, are better explained by propagating electron solitary waves.

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EMHD theory and observations of electron solitary waves in magnetotail plasmas

Cited by 54 publications

References 26 publications

Observations of a Kinetic‐Scale Magnetic Hole in a Reconnection Diffusion Region

Observations of a Kinetic‐Scale Magnetic Hole in a Reconnection Diffusion Region

Electron vortex magnetic holes: A nonlinear coherent plasma structure

Properties and origin of subproton‐scale magnetic holes in the terrestrial plasma sheet

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