scholarly journals Enhanced laser-driven proton acceleration with gas–foil targets

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
Dan Levy ◽  
X. Davoine ◽  
A. Debayle ◽  
L. Gremillet ◽  
V. Malka
Keyword(s):  
Energetic Electron ◽  
Critical Density ◽  
Maximum Energy ◽  
Hydrogen Gas ◽  
Relativistic Electrons ◽  
Back Side ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Gas Layer ◽  
Multidimensional Effects

We study numerically the mechanisms of proton acceleration in gas–foil targets driven by an ultraintense femtosecond laser pulse. The target consists of a near-critical-density hydrogen gas layer of a few tens of microns attached to a $2\ \mathrm {\mu }$ m-thick solid carbon foil with a contaminant thin proton layer at its back side. Two-dimensional particle-in-cell simulations show that, at optimal gas density, the maximum energy of the contaminant protons is increased by a factor of $\sim$ 4 compared with a single foil target. This improvement originates from the near-complete laser absorption into relativistic electrons in the gas. Several energetic electron populations are identified, and their respective effect on the proton acceleration is quantified by computing the electrostatic fields that they generate at the protons’ positions. While each of those electron groups is found to contribute substantially to the overall accelerating field, the dominant one is the relativistic thermal bulk that results from the nonlinear wakefield excited in the gas, as analysed recently by Debayle et al. (New J. Phys., vol. 19, 2017, 123013). Our analysis also reveals the important role of the neighbouring ions in the acceleration of the fastest protons, and the onset of multidimensional effects caused by the time-increasing curvature of the proton layer.

scholarly journals Effective laser driven proton acceleration from near critical density hydrogen plasma

2016 ◽  
Vol 34 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Ashutosh Sharma ◽  
Alexander Andreev
Keyword(s):  
Laser Pulse ◽  
Hydrogen Plasma ◽  
Three Dimensional ◽  
Critical Density ◽  
High Energy ◽  
Intense Laser ◽  
Proton Density ◽  
Proton Acceleration ◽  
Pic Simulation ◽  
Particle In Cell

AbstractRecent advances in the production of high repetition, high power, and short laser pulse have enabled the generation of high-energy proton beam, required for technology and other medical applications. Here we demonstrate the effective laser driven proton acceleration from near-critical density hydrogen plasma by employing the short and intense laser pulse through three-dimensional (3D) particle-in-cell (PIC) simulation. The generation of strong magnetic field is demonstrated by numerical results and scaled with the plasma density and the electric field of laser. 3D PIC simulation results show the ring shaped proton density distribution where the protons are accelerated along the laser axis with fairly low divergence accompanied by off-axis beam of ring-like shape.

scholarly journals Enhanced laser ion acceleration with a multi-layer foam target assembly

2014 ◽  
Vol 32 (4) ◽  
pp. 509-515 ◽  
Author(s):  
E. Yazdani ◽  
R. Sadighi-Bonabi ◽  
H. Afarideh ◽  
J. Yazdanpanah ◽  
H. Hora
Keyword(s):  
Proton Energy ◽  
Critical Density ◽  
Maximum Energy ◽  
Longitudinal Momentum ◽  
Free Electrons ◽  
Particle In Cell ◽  
Direct Laser ◽  
Linearly Polarized ◽  
Cell Simulation ◽  
Laser Acceleration

AbstractInteraction of a linearly polarized Gaussian laser pulse (at relativistic intensity of 2.0 × 1020 Wcm−2) with a multi-layer foam (as a near critical density target) attached to a solid layer is investigated by using two-dimensional particle-in-cell simulation. It is found that electrons with longitudinal momentum exceeding the free electrons limit of meca02/2 so-called super-hot electrons can be produced when the direct laser acceleration regime is fulfilled and benefited from self-focusing inside of the subcritical plasma. These electrons penetrate easily through the target and can enhance greatly the sheath field at the rear, resulting in a significant increase in the maximum energy of protons in target normal sheath acceleration regime. The results indicate that the maximum proton energy is enhanced by 2.7 times via using an assembled target arrangement compared to a bare solid target. Furthermore, by demonstration of this assembly, the maximum proton energy is improved beyond the optimum amount achieved by a two-layer target proposed by Sgattoni et al. (2012).

scholarly journals Enhanced Proton Acceleration by Laser-Driven Collisionless Shock in the Near-Critical Density Target Embedding with Solid Nanolayers

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yue Chao ◽  
Xinxin Yan ◽  
Rui Xie ◽  
Lihua Cao ◽  
Chunyang Zheng ◽  
...  
Keyword(s):  
Critical Density ◽  
Inhomogeneous Magnetic Field ◽  
Shock Acceleration ◽  
Collisionless Shock ◽  
Incident Laser ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Peak Energy ◽  
Accelerated Protons ◽  
Gap Width

Effects of solid nanolayers embedded in a near-critical density plasma on the laser-driven collisionless shock acceleration are investigated by using two-dimensional particle-in-cell simulations. Due to the interaction of nanolayers and the incident laser, an additional number of hot electrons are generated and an inhomogeneous magnetic field is induced. As a result, the collisionless shock is reinforced within the nanolayer gaps compared to the target without the structured nanolayers. When the laser intensity is 9.8 × 10 19  W / cm 2 , the amplitude of the electrostatic field is increased by 30% and the shock velocity is increased from 0.079c to 0.091c, leading to an enhancement of the peak energy and the cutoff energy of accelerated protons, from 6.9 MeV to 9.1 MeV and 12.2 MeV to 20.0 MeV, respectively. Furthermore, the effects of the width of the nanolayer gaps are studied, by adjusting the gap width of nanolayers, and optimal nanolayer setups for collisionless shock acceleration can be acquired.

scholarly journals Characterization of laser-driven proton beams from near-critical density targets using copper activation

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
L. Willingale ◽  
S. R. Nagel ◽  
A. G. R. Thomas ◽  
C. Bellei ◽  
R. J. Clarke ◽  
...  
Keyword(s):  
Critical Density ◽  
High Energy ◽  
Hot Electron ◽  
Channel Formation ◽  
Channel Depth ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Energy Proton ◽  
Target Particle

Copper activation was used to characterize high-energy proton beam acceleration from near-critical density plasma targets. An enhancement was observed when decreasing the target density, which is indicative for an increased laser-accelerated hot electron density at the rear target-vacuum boundary. This is due to channel formation and collimation of the hot electrons inside the target. Particle-in-cell simulations support the experimental observations and show the correlation between channel depth and longitudinal electric field strength is directly correlated with the proton acceleration.

scholarly journals Laser-driven proton acceleration from ultrathin foils with nanoholes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giada Cantono ◽  
Alexander Permogorov ◽  
Julien Ferri ◽  
Evgeniya Smetanina ◽  
Alexandre Dmitriev ◽  
...  
Keyword(s):  
Ultrashort Laser Pulse ◽  
Laser Pulses ◽  
Maximum Energy ◽  
Power Laser ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Target Plasma ◽  
Ultrashort Laser ◽  
Nanometric Size ◽  
Scale Length

AbstractStructured solid targets are widely investigated to increase the energy absorption of high-power laser pulses so as to achieve efficient ion acceleration. Here we report the first experimental study of the maximum energy of proton beams accelerated from sub-micrometric foils perforated with holes of nanometric size. By showing the lack of energy enhancement in comparison to standard flat foils, our results suggest that the high contrast routinely achieved with a double plasma mirror does not prevent damaging of the nanostructures prior to the main interaction. Particle-in-cell simulations support that even a short scale length plasma, formed in the last hundreds of femtoseconds before the peak of an ultrashort laser pulse, fills the holes and hinders enhanced electron heating. Our findings reinforce the need for improved laser contrast, as well as for accurate control and diagnostics of on-target plasma formation.

ENERGETIC PROTON ACCELERATION BY ULTRAINTENSE LASER PULSES IN INHOMOGENEOUS PLASMA TARGETS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 642-646 ◽  
Author(s):  
A. ABUDUREXITI ◽  
Y. MIKADO ◽  
T. OKADA
Keyword(s):  
Laser Pulse ◽  
Inhomogeneous Plasma ◽  
Laser Pulses ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Target Plasma ◽  
Plasma Target ◽  
Experimental Process ◽  
Foil Target ◽  
Proton Bunch

Particle-in-Cell (PIC) simulations of fast particles produced by a short laser pulse with duration of 40 fs and an intensity of 1020W/cm2 interacting with a foil target are performed. The experimental process is numerically simulated by considering a triangular concave target illuminated by an ultraintense laser. We have demonstrated increased acceleration and higher proton energies for triangular concave targets. We also determined the optimum target plasma conditions for maximum proton acceleration. The results indicated that a change in the plasma target shape directly affects the degree of contraction accelerated proton bunch.

Post-solitons and electron vortices generated by femtosecond intense laser interacting with uniform near-critical-density plasmas

2021 ◽  
Author(s):  
Dong-Ning Yue ◽  
Min Chen ◽  
Yao Zhao ◽  
Pan-Fei Geng ◽  
Xiao-Hui Yuan ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Critical Density ◽  
Laser Pulses ◽  
Intense Laser ◽  
Nonlinear Structures ◽  
Particle In Cell ◽  
Laser Propagation ◽  
Laser Driver ◽  
Linearly Polarized ◽  
Dimensional Simulation

Abstract Generation of nonlinear structures, such as stimulated Raman side scattering waves, post-solitons and electron vortices, during ultra-short intense laser pulse transportation in near-critical-density (NCD) plasmas are studied by using multi-dimensional particle-in-cell (PIC) simulations. In two-dimensional geometries, both P- and S- polarized laser pulses are used to drive these nonlinear structures and to check the polarization effects on them. In the S-polarized case, the scattered waves can be captured by surrounding plasmas leading to the generation of post-solitons, while the main pulse excites convective electric currents leading to the formation of electron vortices through Kelvin-Helmholtz instability (KHI). In the P-polarized case, the scattered waves dissipate their energy by heating surrounding plasmas. Electron vortices are excited due to the hosing instability of the drive laser. These polarization dependent physical processes are reproduced in two different planes perpendicular to the laser propagation direction in three-dimensional simulation with linearly polarized laser driver. The current work provides inspiration for future experiments of laser-NCD plasma interactions.

Microinstabilities and plasma waves at Near-Sun Solar Wind collisionless Shocks: Predictions for PSP and SO

2021 ◽  
Author(s):  
Zhongwei Yang ◽  
Shuichi Matsukiyo ◽  
Huasheng Xie ◽  
Fan Guo ◽  
Mingzhe Liu ◽  
...  
Keyword(s):  
Solar Wind ◽  
Shock Front ◽  
Leading Edge ◽  
Relativistic Electrons ◽  
Interplanetary Shocks ◽  
Particle In Cell ◽  
Drift Instability ◽  
Shock Simulation ◽  
Mass Ejection ◽  
The Impact

<p><span>Microinstabilities and waves excited at perpendicular interplanetary shocks in the near-Sun solar wind are investigated by full particle-in-cell simulations. By analyzing the dispersion relation of fluctuating field components directly issued from the shock simulation, we obtain key findings concerning wave excitations at the shock front: (1) at the leading edge of the foot, two types of electrostatic (ES) waves are observed. The relative drift of the reflected ions versus the electrons triggers an electron cyclotron drift instability (ECDI) that excites the first ES wave. Because the bulk velocity of gyro-reflected ions shifts to the direction of the shock front, the resulting ES wave propagates obliquely to the shock normal. Immediately, a fraction of incident electrons are accelerated by this ES wave and a ring-like velocity distribution is generated. They can couple with the hot Maxwellian core and excite the second ES wave around the upper hybrid frequency. (2) From the middle of the foot all the way to the ramp, electrons can couple with both incident and reflected ions. ES waves excited by ECDI in different directions propagate across each other. Electromagnetic (EM) waves (X mode) emitted toward upstream are observed in both regions. They are probably induced by a small fraction of relativistic electrons. The impact of shock front rippling, Mach numbers, and dimensions on the ES wave excitation also will be discussed. Results shed new insight on the mechanism for the occurrence of ES wave excitations and possible EM wave emissions at young coronal mass ejection–driven shocks in the near-Sun solar wind.</span></p>

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