Shocks in collisionless plasmas

Parks, G. K.; Lee, E.; Fu, S. Y.; Lin, N.; Liu, Y.; Yang, Zhongwei

doi:10.1007/s41614-017-0003-4

Cited by 20 publications

(13 citation statements)

References 106 publications

(147 reference statements)

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“…The terrestrial bow shock is formed by a continuous interaction between the supersonic solar wind and Earth's magnetic field (Eastwood et al, ; Tsurutani et al, ). It has been intensively studied over the last few decades from both theoretical and experimental standpoints (e.g., Parks et al, , and references therein). Spreiter et al () introduced an Magnetohydrodynamic (MHD) model of the interaction between the solar wind and the magnetosphere.…”

Section: Introductionmentioning

confidence: 99%

Statistical Survey of the Terrestrial Bow Shock Observed by the Cluster Spacecraft

et al. 2019

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The terrestrial bow shock provides us with a unique opportunity to extensively investigate properties of collisionless shocks using in situ measurements under a wide range of upstream conditions. Here we report a statistical study of 529 terrestrial bow shock crossings observed between years 2001 and 2013 by the four Cluster spacecraft. By applying a simple timing method to multipoint measurements, we are able to investigate their characteristic spatiotemporal features. We have found a significant correlation between the speed of the bow shock motion and the solar wind speed. We have also compared obtained speeds with time derivatives of locations predicted by a three-dimensional bow shock model. Finally, we provide a list of bow shock crossings for possible further investigation by the scientific community. Plain Language SummaryThe Sun is continuously emitting a stream of charged particles-called the solar wind-from its upper atmosphere. The terrestrial magnetosphere forms the obstacle to its flow. Due to supersonic speed of the solar wind, the bow shock is created ahead of the magnetosphere. This abrupt transition region between supersonic and subsonic flows has been frequently observed by the four Cluster spacecraft. Using a timing analysis, we have retrieved speed and directions of the bow shock motion for a large number of crossings. We have correlated the bow shock speed with the solar wind speed and predictions of the bow shock locations by the empirical model. A better understanding of the bow shock kinematics may bring new insights to wave-particle interactions with applications in laboratory plasmas.

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Section: Introductionmentioning

confidence: 99%

Statistical Survey of the Terrestrial Bow Shock Observed by the Cluster Spacecraft

et al. 2019

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“…A number of unique features make parallel and quasiparallel shocks a subject of particular interest. Spacecraft have observed density and temperature anomalies within parallel shocks whose origin is not yet understood [10,11]. Simulations show that parallel shocks (at high Mach numbers [12]) are not steady-state, but continuously reform [13] in a turbulent process that has never been observed in the laboratory.…”

Section: Introductionmentioning

confidence: 99%

Observations of a field-aligned ion/ion-beam instability in a magnetized laboratory plasma

et al. 2018

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Collisionless coupling between super Alfvénic ions and an ambient plasma parallel to a background magnetic field is mediated by a set of electromagnetic ion/ion-beam instabilities including the resonant right hand instability (RHI). To study this coupling and its role in parallel shock formation, a new experimental configuration at the University of California, Los Angeles utilizes high-energy and high-repetition-rate lasers to create a super-Alfvénic field-aligned debris plasma within an ambient plasma in the Large Plasma Device (LAPD). We used a time-resolved fluorescence monochromator and an array of Langmuir probes to characterize the laser plasma velocity distribution and density. The debris ions were observed to be sufficiently super-Alfvénic and dense to excite the RHI. Measurements with magnetic flux probes exhibited a right-hand circularly polarized frequency chirp consistent with the excitation of the RHI near the laser target. We compared measurements to 2D hybrid simulations of the experiment.

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“…Studies of shock kinetic properties mostly focus on the Earth's bow shock (e.g., Wilson et al 2014a,b;Möbius et al 2001;Lee et al 2009;Parks et al 2012Parks et al , 2013Parks et al , 2017Yang et al 2014Yang et al , 2016.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Properties of an Interplanetary Shock Propagating inside a Coronal Mass Ejection

Liu

Yang

et al. 2018

ApJL

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We investigate the kinetic properties of a typical fast-mode shock inside an interplanetary coronal mass ejection (ICME) observed on 1998 August 6 at 1 AU, including particle distributions and wave analysis with the in situ measurements from Wind .Key results are obtained concerning the shock and the shock-ICME interaction at kinetic scales: (1) gyrating ions, which may provide energy dissipation at the shock in addition to wave-particle interactions, are observed around the shock ramp; (2) despite the enhanced proton temperature anisotropy of the shocked plasma, the low plasma β inside the ICME constrains the shocked plasma under the thresholds of the ion cyclotron and mirror-mode instabilities; (3) whistler heat flux instabilities, which can pitch-angle scatter halo electrons through a cyclotron resonance, are observed around the shock, and can explain the disappearance of bidirectional electrons inside the ICME together with normal betatron acceleration; (4) whistler waves near the shock are likely 2 Liu et al.associated with the whistler heat flux instabilities excited at the shock ramp, which is consistent with the result that the waves may originate from the shock ramp; (5) the whistlers share a similar characteristic with the shocklet whistlers observed by Wilson et al, providing possible evidence that the shock is decaying because of the strong magnetic field inside the ICME.

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Shocks in collisionless plasmas

Cited by 20 publications

References 106 publications

Statistical Survey of the Terrestrial Bow Shock Observed by the Cluster Spacecraft

Statistical Survey of the Terrestrial Bow Shock Observed by the Cluster Spacecraft

Observations of a field-aligned ion/ion-beam instability in a magnetized laboratory plasma

Kinetic Properties of an Interplanetary Shock Propagating inside a Coronal Mass Ejection

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