Observation of Collisionless Shocks in Laser-Plasma Experiments

Romagnani, L.; Bulanov, S. V.; Borghesi, M.; Audebert, P.; Gauthier, J. C.; Löwenbrück, K.; Mackinnon, A. J.; Patel, P. K.; Pretzler, G.; Toncian, T.; Willi, O.

doi:10.1103/physrevlett.101.025004

Cited by 159 publications

(151 citation statements)

References 13 publications

(7 reference statements)

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“…[21]. In this configuration, similar to the configuration employed in recent experiments [6,7], two symmetric shocks moving in opposite directions (along x) are launched from the contact discontinuity at the center of the simulation box, where the two plasma shells initially come in contact. The region between the two shocks defines the downstream of the two nonlinear structures.…”

mentioning

confidence: 99%

“…Collisionless shocks have been studied for many decades, mainly in the context of space and astrophysics [1][2][3][4]. Recently, shock acceleration raised significant interest in the quest for a laser-based ion acceleration scheme due to an experimentally demonstrated high beam quality [5][6][7][8].Interpenetrating plasma slabs of hot electrons and cold ions are acting to set up the electrostatic fields via longitudinal plasma instabilities. The lighter electrons leaving the denser regions are held back by the electric fields, which pull the ions.…”

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confidence: 99%

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Electromagnetic Field Generation in the Downstream of Electrostatic Shocks Due to Electron Trapping

et al. 2014

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A new magnetic field generation mechanism in electrostatic shocks is found, which can produce fields with magnetic energy density as high as 0.01 of the kinetic energy density of the flows on time scales ∼10 4 ω −1 pe . Electron trapping during the shock formation process creates a strong temperature anisotropy in the distribution function, giving rise to the pure Weibel instability. The generated magnetic field is well confined to the downstream region of the electrostatic shock. The shock formation process is not modified, and the features of the shock front responsible for ion acceleration, which are currently probed in laserplasma laboratory experiments, are maintained. However, such a strong magnetic field determines the particle trajectories downstream and has the potential to modify the signatures of the collisionless shock. Collisionless shocks have been studied for many decades, mainly in the context of space and astrophysics [1][2][3][4]. Recently, shock acceleration raised significant interest in the quest for a laser-based ion acceleration scheme due to an experimentally demonstrated high beam quality [5][6][7][8].Interpenetrating plasma slabs of hot electrons and cold ions are acting to set up the electrostatic fields via longitudinal plasma instabilities. The lighter electrons leaving the denser regions are held back by the electric fields, which pull the ions. Particles are trapped in the associated electrostatic potential, which steepens and eventually reaches a quasisteady-state collisionless electrostatic shock. Most of the theoretical work dates back to the 1970s [9-13] relying on the pseudo-Sagdeev potential [14] and progress has been mainly triggered by kinetic simulations [15][16][17][18].The short formation time scales and the one dimensionality of the problem make it easily accessible with theory and computer simulations. However, long time shock evolution was often one dimensional or electrostatic codes were used, and the role of electromagnetic modes was mostly neglected. More advanced multidimensional simulations have shown the importance of electromagnetic modes also in this context, due to transverse modes which are excited on the ion time scale [19,20]. We show that in the case of very high electron temperatures associated with the formation of electrostatic shocks [21], electromagnetic modes become important on electron time scales, creating strong magnetic fields in the downstream of the shock.With the increase in laser energy and intensity, the possibility to drive electrostatic shocks has become important for laboratory experiments of electrostatic shocks. Recent laser-driven shock experiments showed the appearance of an electromagnetic field structure [22][23][24], which was attributed to the ion-filamentation instability [25] that evolves on time scales of ten thousands of the inverse electron plasma frequency, ω −1 pe . As a main outcome of this Letter, we show that these structures can already be seeded and produced on tens of ω −1 pe and remain in a quasisteady state over t...

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Electromagnetic Field Generation in the Downstream of Electrostatic Shocks Due to Electron Trapping

et al. 2014

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“…Related studies include counter-streaming laser-produced plasmas supporting hohlraum design for indirect-drive inertial confinement fusion [17][18][19] and for studying astrophysically relevant shocks, [20][21][22][23][24] colliding plasmas using wire-array Z pinches, 25,26 and applications such as pulsed laser deposition 27 and laser-induced breakdown spectroscopy. 28 Primary issues of interest in these studies include the identification of shock formation, the formation of a stagnation layer [29][30][31] between colliding plasmas, and the possible role of two-fluid and kinetic effects on plasma interpenetration.…”

Section: Introductionmentioning

confidence: 99%

Experimental evidence for collisional shock formation via two obliquely merging supersonic plasma jets

et al. 2014

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We report spatially resolved measurements of the oblique merging of two supersonic laboratory plasma jets. The jets are formed and launched by pulsed-power-driven railguns using injected argon, and have electron density ∼ 10 14 cm −3 , electron temperature ≈ 1.4 eV, ionization fraction near unity, and velocity ≈ 40 km/s just prior to merging. The jet merging produces a few-cm-thick stagnation layer, as observed in both fastframing camera images and multi-chord interferometer data, consistent with collisional shock formation [E. C. Merritt et al., Phys. Rev. Lett. 111, 085003 (2013)].

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“…In order to generate the astrophysical phenomena in laboratory scale, a hypersonic plasma flow obtained by a laser ablation or a pulsed-power discharge is considered [8][9][10][11][12][13]. The hypersonic plasma flow obtained by the laser ablation techniques is required the intense laser due to the energy deposition on a solid target.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Scale Experiments for Collisionless Shock Generated by Taper-Cone-Shaped Plasma Focus Device

Sasaki

Kinase²,

Takezaki³

et al. 2014

Proceedings of the 12th Asia Pacific Physics Conference (APPC12)

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To obtain the collisionless shock, the hypersonic plasma flow generated by a taper-cone-shaped plasma focus device is proposed to evaluate in these shocks. The results shows that the velocity of shock wave is estimated to be about 15 km/s observed by the streak camera. The evolution of the shock wave with applied magnetic field was measured. The decreasing shock velocity was observed at the applied region of magnetic field. The result indicates that the magnetic pressure affects the decreasing shock velocity.

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Observation of Collisionless Shocks in Laser-Plasma Experiments

Cited by 159 publications

References 13 publications

Electromagnetic Field Generation in the Downstream of Electrostatic Shocks Due to Electron Trapping

Electromagnetic Field Generation in the Downstream of Electrostatic Shocks Due to Electron Trapping

Experimental evidence for collisional shock formation via two obliquely merging supersonic plasma jets

Laboratory Scale Experiments for Collisionless Shock Generated by Taper-Cone-Shaped Plasma Focus Device

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