Electron cyclotron microinstability in the foot of a perpendicular shock: A self-consistent PIC simulation

Muschietti, L.; Lembège, Bertrand

doi:10.1016/j.asr.2005.03.077

Cited by 40 publications

(47 citation statements)

References 19 publications

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“…Wavelengths are such that kρ e ∼ 1. The instability has been identified in 1-D shock simulations (Muschietti and Lembège, 2006), reported in the 2-D simulations of Matsukiyo and Scholer (2006), and studied in detail in Muschietti and Lembège (2013) for strictly perpendicular propagation. We encounter it here again for an angle 6 • off perpendicular as visible in Figs.…”

Section: Discussionmentioning

confidence: 99%

Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks

Muschietti

Lembège

2017

Ann. Geophys.

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Abstract. Quasi-perpendicular supercritical shocks are characterized by the presence of a magnetic foot due to the accumulation of a fraction of the incoming ions that is reflected by the shock front. There, three different plasma populations coexist (incoming ion core, reflected ion beam, electrons) and can excite various two-stream instabilities (TSIs) owing to their relative drifts. These instabilities represent local sources of turbulence with a wide frequency range extending from the lower hybrid to the electron cyclotron. Their linear features are analyzed by means of both a dispersion study and numerical PIC simulations. Three main types of TSI and correspondingly excited waves are identified:i. Oblique whistlers due to the (so-called "fast") relative drift between reflected ions/electrons; the waves propagate toward upstream away from the shock front at a strongly oblique angle (θ ∼ 50 • ) to the ambient magnetic field B o , have frequencies a few times the lower hybrid, and have wavelengths a fraction of the ion inertia length c/ω pi .ii. Quasi-perpendicular whistlers due to the (so-called "slow") relative drift between incoming ions/electrons; the waves propagate toward the shock ramp at an angle θ a few degrees off 90 • , have frequencies around the lower hybrid, and have wavelengths several times the electron inertia length c/ω pe .iii. Extended Bernstein waves which also propagate in the quasi-perpendicular domain, yet are due to the (so-called "fast") relative drift between reflected ions/electrons; the instability is an extension of the electron cyclotron drift instability (normally strictly perpendicular and electrostatic) and produces waves with a magnetic component which have frequencies close to the electron cyclotron as well as wavelengths close to the electron gyroradius and which propagate toward upstream.Present results are compared with previous works in order to stress some features not previously analyzed and to define a more synthetic view of these TSIs.

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Section: Discussionmentioning

confidence: 99%

Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks

Muschietti

Lembège

2017

Ann. Geophys.

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“…23,24 Since most of the microinstabilities are inseparable with electron dynamics, their nonlinear evolutions in self-consistently reproduced shock structures in PIC simulations are studied only recently, [25][26][27][28] except for Refs. [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Mach number dependence of electron heating in high Mach number quasiperpendicular shocks

Matsukiyo

2010

Physics of Plasmas

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The efficiency of electron heating through microinstabilities generated in the transition region of a quasiperpendicular shock for a wide range of Mach numbers is investigated by utilizing particle-in-cell ͑PIC͒ simulation and model analyses. In the model analyses saturation levels of effective electron temperature as a result of microinstabilities are estimated from an extended quasilinear ͑trapping͒ analysis for relatively low ͑high͒ Mach number shocks. Here, modified two-stream instability ͑MTSI͒ is assumed to become dominant in low Mach number regime, while Buneman instability ͑BI͒ is assumed to become dominant in high Mach number regime. It is revealed that Mach number dependence of the effective electron temperature in the MTSI dominant case is essentially different from that in the BI dominant case. The effective electron temperature through the MTSI does not depend much on the Mach number, although that through the BI increases with the Mach number as in the past studies. The results are confirmed to be consistent with the PIC simulations both in qualitative and quantitative levels. The model analyses predict that a critical Mach number, above which a steep rise in electron heating rate occurs, may arise at the Mach number of a few tens.

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“…The continuity equation for charge is also solved to compute the exact current density given by the motion of charged particles 27 . In the present simulation, the simulation domain is taken in the shock-rest frame 11,[28][29][30] . A collisionless shock is excited by the "relaxation" between a supersonic plasma flow and a subsonic plasma flow moving in the same direc-tion.…”

Section: Simulation Setupmentioning

confidence: 99%

“…At lower-Mach-number (M A < 10) perpendicular shocks, the relative velocity between incoming electrons and incoming/reflected ions becomes close to the electron thermal velocity. Then, the growth rate of the BI becomes small because of the damping by thermal electrons, and the ECDI becomes dominant, which excites electrostatic waves at multiple electron cyclotron harmonic frequencies 11 . When the relative velocity between incoming electrons and incoming/reflected ions becomes slower than the electron thermal velocity at lowerMach-number perpendicular shocks, high-frequency electrostatic waves are not excited due to the damping by thermal electrons, and the modified two-stream instability (MTSI) [12][13][14][15][16] becomes dominant.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and microinstabilities at perpendicular collisionless shock: A comparison of large-scale two-dimensional full particle simulations with different ion to electron mass ratio

Umeda¹,

Kidani²,

Matsukiyo³

et al. 2014

Physics of Plasmas

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Large-scale two-dimensional (2D) full particle-in-cell simulations are carried out for studying the relationship between the dynamics of a perpendicular shock and microinstabilities generated at the shock foot. The structure and dynamics of collisionless shocks are generally determined by Alfven Mach number and plasma beta, while microinstabilities at the shock foot are controlled by the ratio of the upstream bulk velocity to the electron thermal velocity and the ratio of the plasma-to-cyclotron frequency. With a fixed Alfven Mach number and plasma beta, the ratio of the upstream bulk velocity to the electron thermal velocity is given as a function of the ion-to-electron mass ratio. The present 2D full PIC simulations with a relatively low Alfven Mach number (M A ∼ 6) show that the modified two-stream instability is dominant with higher ion-to-electron mass ratios. It is also confirmed that waves propagating downstream are more enhanced at the shock foot near the shock ramp as the mass ratio becomes higher. The result suggests that these waves play a role in the modification of the dynamics of collisionless shocks through the interaction with shock front ripples.

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Electron cyclotron microinstability in the foot of a perpendicular shock: A self-consistent PIC simulation

Cited by 40 publications

References 19 publications

Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks

Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks

Mach number dependence of electron heating in high Mach number quasiperpendicular shocks

Dynamics and microinstabilities at perpendicular collisionless shock: A comparison of large-scale two-dimensional full particle simulations with different ion to electron mass ratio

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