Shock ion acceleration by an ultrashort circularly polarized laser pulse via relativistic transparency in an exploded target

Kim, Young-Kuk; Cho, Myung Hoon; Song, Hyung Seon; Kang, Tae Uk; Park, Hyung Ju; Jung, Moon Youn; Hur, Min Sup

doi:10.1103/physreve.92.043102

Cited by 19 publications

(5 citation statements)

References 41 publications

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“…Second, in a dense enough plasma, the front-side ions are pushed by the 'laser piston', i.e., the space-charge field resulting from the laser ponderomotive force on the electrons. Third, under specific conditions, the laser piston or the electron pressure gradients created in an inhomogeneous plasma can launch a collisionless electrostatic shock [67][68][69][70], accelerating a fraction of the background ions to energies possibly larger than through TNSA [60,[71][72][73][74]. Further, for tightly focused lasers, ion acceleration can proceed via the electric field induced by magnetic vortices moving down density gradients [75,76].…”

Section: Introductionmentioning

confidence: 99%

Electron heating by intense short-pulse lasers propagating through near-critical plasmas

et al. 2017

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We investigate the electron heating induced by a relativistic-intensity laser pulse propagating through a near-critical plasma. Using particle-in-cell simulations, we show that a specific interaction regime sets in when, due to the energy depletion caused by the plasma wakefield, the laser front profile has steepened to the point of having a length scale close to the laser wavelength. Wave breaking and phase mixing have then occurred, giving rise to a relativistically hot electron population following the laser pulse. This hot electron flow is dense enough to neutralize the cold bulk electrons during their backward acceleration by the wakefield. This neutralization mechanism delays, but does not prevent the breaking of the wakefield: the resulting phase mixing converts the large kinetic energy of the backward-flowing electrons into thermal energy greatly exceeding the conventional ponderomotive scaling at laser intensities > -10 W cm 21 2 and gas densities around 10% of the critical density. We develop a semi-numerical model, based on the Akhiezer-Polovin equations, which correctly reproduces the particle-in-cell-predicted electron thermal energies over a broad parameter range. Given this good agreement, we propose a criterion for full laser absorption that includes field-induced ionization. Finally, we show that our predictions still hold in a two-dimensional geometry using a realistic gas profile.

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Section: Introductionmentioning

confidence: 99%

Electron heating by intense short-pulse lasers propagating through near-critical plasmas

et al. 2017

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“…For 2D PIC simulation, we used our in-house code, cplPIC, which has been verified for numerous applications of laser-plasmas. [25][26][27][28][29] The cplPIC code employs the standard Yee-mesh-based field solver, 30 Villasenor-Buneman charge-conserving scheme for current calculation, 31 and Boris mover for particle motion. 32 For field ionization of neutral particles by the laser field, we used the barrier-suppression ionization (BSI) model 33 for electric field larger than the critical field EðtÞ > E crit and ADK (Ammosov-Delone-Krainov) tunneling ionization model, 34 otherwise : The critical electric field is given by 35…”

Section: Simulation Setupmentioning

confidence: 99%

Intense narrowband terahertz pulses produced by obliquely colliding laser pulses in helium gas

et al. 2023

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A practical configuration for generating narrowband terahertz (THz) pulses based on plasma dipole oscillations (PDOs) is studied using two-dimensional particle-in-cell simulations. In this scheme, two slightly detuned laser pulses collide obliquely in a helium gas. Plasma strips are generated along the paths of the laser pulses by field ionization. The PDO created in the overlap region of the two laser pulses emits a THz pulse with a peak electric field strength of a few gigavolt per meter. An energy conversion efficiency of 0.542 × 10 − 3 is achieved for laser pulse intensities 4.82 × 10 16 W / c m 2, a spot radii of 5 μ m, and a collision angle of 10.8 °. A force balance model is extended for the obliquely colliding configuration of the pulses. As the complications, such as generating plasmas separately or aligning the beams with preformed plasma, are eliminated from our new configuration, this makes a future experimental study of PDO more straightforward.

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“…Another necessary condition is a fast-enough hole-boring speed to match the sound speed, so the compressed density layer from the hole-boring process is converted into the shock eventually. Previously, we revealed that the relativistically transmitting pulse energy is the major heating source in CP-driven shock [21]. In low-initial-density plasma, the transmittance is high and so is the sound speed.…”

Section: -2mentioning

confidence: 99%

“…Previously, we suggested using the relativistic transparency for shock generation by circularly polarized (CP) pulses [21], where hot-electron recirculation is not available. Regarding the effects of transmittance on shock formation, there have been seemingly contradictory results; Zhang et al could obtain a quasimonoenergetic carbon beam of ∼7.5 MeV from an * mshur@unist.ac.kr opaque plasma irradiated by an LP pulse but could not do so in transparent plasma [22].…”

Section: Introductionmentioning

confidence: 99%

Effects of laser polarizations on shock generation and shock ion acceleration in overdense plasmas

et al. 2016

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The effects of laser-pulse polarization on the generation of an electrostatic shock in an overdense plasma were investigated using particle-in-cell simulations. We found, from one-dimensional simulations, that total and average energies of reflected ions from a circular polarization-(CP) driven shock front are a few times higher than those from a linear polarization-(LP) driven one for a given pulse energy. Moreover, it was discovered that the pulse transmittance is the single dominant factor for determining the CP-shock formation, while the LP shock is affected by the plasma scale length as well as the transmittance. In two-dimensional simulations, it is observed that the transverse instability, such as Weibel-like instability, can be suppressed more efficiently by CP pulses.

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Shock ion acceleration by an ultrashort circularly polarized laser pulse via relativistic transparency in an exploded target

Cited by 19 publications

References 41 publications

Electron heating by intense short-pulse lasers propagating through near-critical plasmas

Electron heating by intense short-pulse lasers propagating through near-critical plasmas

Intense narrowband terahertz pulses produced by obliquely colliding laser pulses in helium gas

Effects of laser polarizations on shock generation and shock ion acceleration in overdense plasmas

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