Evolution of slow electrostatic shock into a plasma shock mediated by electrostatic turbulence

Dieckmann, Mark E; Sarri, Gianluca; Doria, D.; Ahmed, H.; Borghesi, M.

doi:10.1088/1367-2630/16/7/073001

Cited by 18 publications

(24 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This instability is known to destroy planar double layers and electrostatic shocks (Karimabadi et al 1991;Kato & Takabe 2010;Dieckmann et al 2015a) and here we have shown that it also affects the nonplanar ones.…”

Section: Discussionsupporting

confidence: 50%

The interplay of the collisionless non-linear thin-shell instability with the ion acoustic instability

Dieckmann

Folini

Walder

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

The nonlinear thin-shell instability (NTSI) may explain some of the turbulent hydrodynamic structures that are observed close to the collision boundary of energetic astrophysical outflows. It develops in nonplanar shells that are bounded on either side by a hydrodynamic shock, provided that the amplitude of the seed oscillations is sufficiently large. The hydrodynamic NTSI has a microscopic counterpart in collisionless plasma. A sinusoidal displacement of a thin shell, which is formed by the collision of two clouds of unmagnetized electrons and protons, grows and saturates on timescales of the order of the inverse proton plasma frequency. Here we increase the wavelength of the seed perturbation by a factor 4 compared to that in a previous study. Like in the case of the hydrodynamic NTSI, the increase in the wavelength reduces the growth rate of the microscopic NTSI. The prolonged growth time of the microscopic NTSI allows the waves, which are driven by the competing ion acoustic instability, to grow to a large amplitude before the NTSI saturates and they disrupt the latter. The ion acoustic instability thus imposes a limit on the largest wavelength that can be destabilized by the NTSI in collisionless plasma. The limit can be overcome by binary collisions. We bring forward evidence for an overstability of the collisionless NTSI.

show abstract

Section: Discussionsupporting

confidence: 50%

The interplay of the collisionless non-linear thin-shell instability with the ion acoustic instability

Dieckmann

Folini

Walder

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…Simulations have shown that drift instabilities and electrostatic turbulence can in some cases suppress the growth of a magnetosonic wave. 3 As we go to higher flow speeds, the plasma shocks become magnetized by filamentation instabilities. [4][5][6][7] We consider here shocks, which develop in an initially unmagnetized and collisionless plasma.…”

Section: Introductionmentioning

confidence: 99%

“…17 Obliquely propagating ion acoustic waves grow in the foreshock region and modulate the incoming upstream ions. The plasma shock is either transformed into a shock with a broad transition layer 3 or it is destroyed by the inflowing turbulent plasma. 16 Previous simulation studies have addressed the evolution of (quasi-)planar plasma shocks.…”

Section: Introductionmentioning

confidence: 99%

Shocks in unmagnetized plasma with a shear flow: Stability and magnetic field generation

et al. 2015

View full text Add to dashboard Cite

A pair of curved shocks in a collisionless plasma is examined with a two-dimensional particle-incell (PIC) simulation. The shocks are created by the collision of two electron-ion clouds at a speed that exceeds everywhere the threshold speed for shock formation. A variation of the collision speed along the initially planar collision boundary, which is comparable to the ion acoustic speed, yields a curvature of the shock that increases with time. The spatially varying Mach number of the shocks results in a variation of the downstream density in the direction along the shock boundary. This variation is eventually equilibrated by the thermal diffusion of ions. The pair of shocks is stable for tens of inverse ion plasma frequencies. The angle between the mean flow velocity vector of the inflowing upstream plasma and the shock's electrostatic field increases steadily during this time. The disalignment of both vectors gives rise to a rotational electron flow, which yields the growth of magnetic field patches that are coherent over tens of electron skin depths.

show abstract

“…The LH and electron cyclotron drift instabilities will drive waves with wavevectors that are aligned with the electron drift speed. 31,40,41 These drift instabilities are thus suppressed by the one-dimensional simulation geometry.…”

Section: Phys Plasmas 23 062111 (2016)mentioning

confidence: 99%

“…4,6,31 The LH shock is modified by the magnetic field it is piling up as it expands into the upstream region. The magnetic pressure gradient force it exerts on the ambient ions in the upstream region is pre-accelerating them, which reduces the ion velocity change at the shock to a value that is comparable to or below the phase speed of the LH wave.…”

Section: Introductionmentioning

confidence: 99%

Particle-in-cell simulation study of a lower-hybrid shock

et al. 2016

View full text Add to dashboard Cite

Articles you may be interested in 3D electrostatic gyrokinetic electron and fully kinetic ion simulation of lower-hybrid drift instability of Harris current sheet Phys. Plasmas 23, 072104 (2016); 10.1063/1.4954830 Nonlinear electromagnetic formulation for particle-in-cell simulation of lower hybrid waves in toroidal geometry Phys. Plasmas 23, 062501 (2016); 10.1063/1.4952773A study of the early-stage evolution of relativistic electron-ion shock using three-dimensional particle-in-cell simulations Phys. Plasmas 21, 072905 (2014) Particle-in-cell simulation study of a lower-hybrid shock The expansion of a magnetized high-pressure plasma into a low-pressure ambient medium is examined with particle-in-cell simulations. The magnetic field points perpendicular to the plasma's expansion direction and binary collisions between particles are absent. The expanding plasma steepens into a quasi-electrostatic shock that is sustained by the lower-hybrid (LH) wave. The ambipolar electric field points in the expansion direction and it induces together with the background magnetic field a fast E cross B drift of electrons. The drifting electrons modify the background magnetic field, resulting in its pile-up by the LH shock. The magnetic pressure gradient force accelerates the ambient ions ahead of the LH shock, reducing the relative velocity between the ambient plasma and the LH shock to about the phase speed of the shocked LH wave, transforming the LH shock into a nonlinear LH wave. The oscillations of the electrostatic potential have a larger amplitude and wavelength in the magnetized plasma than in an unmagnetized one with otherwise identical conditions. The energy loss to the drifting electrons leads to a noticeable slowdown of the LH shock compared to that in an unmagnetized plasma. Published by AIP Publishing.

show abstract

Evolution of slow electrostatic shock into a plasma shock mediated by electrostatic turbulence

Cited by 18 publications

References 72 publications

The interplay of the collisionless non-linear thin-shell instability with the ion acoustic instability

The interplay of the collisionless non-linear thin-shell instability with the ion acoustic instability

Shocks in unmagnetized plasma with a shear flow: Stability and magnetic field generation

Particle-in-cell simulation study of a lower-hybrid shock

Contact Info

Product

Resources

About