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.

scholarly journals Efficient Laser-Driven Proton Acceleration from a Cryogenic Solid Hydrogen Target

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
J. Polz ◽  
A. P. L. Robinson ◽  
A. Kalinin ◽  
G. A. Becker ◽  
R. A. Costa Fraga ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Solid Hydrogen ◽  
Successful Implementation ◽  
Power Laser ◽  
Hydrogen Target ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Thermal Features ◽  
Terawatt Laser

Abstract We report on the successful implementation and characterization of a cryogenic solid hydrogen target in experiments on high-power laser-driven proton acceleration. When irradiating a solid hydrogen filament of 10 μm diameter with 10-Terawatt laser pulses of 2.5 J energy, protons with kinetic energies in excess of 20 MeV exhibiting non-thermal features in their spectrum were observed. The protons were emitted into a large solid angle reaching a total conversion efficiency of several percent. Two-dimensional particle-in-cell simulations confirm our results indicating that the spectral modulations are caused by collisionless shocks launched from the surface of the the high-density filament into a low-density corona surrounding the target. The use of solid hydrogen targets may significantly improve the prospects of laser-accelerated proton pulses for future applications.

scholarly journals Enhanced laser-driven proton acceleration using nanowire targets

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Vallières ◽  
M. Salvadori ◽  
A. Permogorov ◽  
G. Cantono ◽  
K. Svendsen ◽  
...  
Keyword(s):  
Proton Energy ◽  
Hot Electrons ◽  
Power Laser ◽  
Nanowire Diameter ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
Physical Mechanisms ◽  
Proton Temperature ◽  
Matter Interaction ◽  
Nanostructured Target

AbstractLaser-driven proton acceleration is a growing field of interest in the high-power laser community. One of the big challenges related to the most routinely used laser-driven ion acceleration mechanism, Target-Normal Sheath Acceleration (TNSA), is to enhance the laser-to-proton energy transfer such as to maximize the proton kinetic energy and number. A way to achieve this is using nanostructured target surfaces in the laser-matter interaction. In this paper, we show that nanowire structures can increase the maximum proton energy by a factor of two, triple the proton temperature and boost the proton numbers, in a campaign performed on the ultra-high contrast 10 TW laser at the Lund Laser Center (LLC). The optimal nanowire length, generating maximum proton energies around 6 MeV, is around 1–2 $$\upmu$$ μ m. This nanowire length is sufficient to form well-defined highly-absorptive NW forests and short enough to minimize the energy loss of hot electrons going through the target bulk. Results are further supported by Particle-In-Cell simulations. Systematically analyzing nanowire length, diameter and gap size, we examine the underlying physical mechanisms that are provoking the enhancement of the longitudinal accelerating electric field. The parameter scan analysis shows that optimizing the spatial gap between the nanowires leads to larger enhancement than by the nanowire diameter and length, through increased electron heating.

scholarly journals High quality GeV proton beams from a density-modulated foil target

2009 ◽  
Vol 27 (4) ◽  
pp. 611-617 ◽  
Author(s):  
T.P. Yu ◽  
M. Chen ◽  
A. Pukhov
Keyword(s):  
Laser Intensity ◽  
Laser Pulses ◽  
Two Dimensional ◽  
High Quality ◽  
Proton Acceleration ◽  
Circularly Polarized ◽  
Particle In Cell ◽  
Efficient Energy ◽  
Peak Energy ◽  
Foil Target

AbstractWe study proton acceleration from a foil target with a transversely varying density using multi-dimensional Particle-in-Cell (PIC) simulations. In order to reduce electron heating and deformation of the target, circularly polarized Gaussian laser pulses at intensities on the order of 1022 Wcm−2 are used. It is shown that when the target density distribution fits that of the laser intensity profile, protons accelerated from the center part of the target have quasi-monoenergetic spectra and are well collimated. In our two-dimensional PIC simulations, the final peak energy can be up to 1.4 GeV with the full-width of half maximum divergence cone of less than 4°. We observe highly efficient energy conversion from the laser to the protons in the simulations.

scholarly journals FDTD Modeling of double ultrashort pulse propagation in nonlinear absorbing media

2020 ◽  
Vol 238 ◽  
pp. 12006
Author(s):  
J.D. Pisonero ◽  
O. Varela ◽  
E. García ◽  
I. Hernández ◽  
J. Ajates ◽  
...  
Keyword(s):  
Finite Difference Time Domain ◽  
Pulse Propagation ◽  
Fdtd Method ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Power Laser ◽  
Ultrashort Pulse Propagation ◽  
Absorbing Media ◽  
Ultrashort Laser ◽  
Difference Time

An approach based on the finite-difference time-domain (FDTD) method is developed for simulating the dynamics of two ultrashort laser pulses inside a saturable absorbing media. This work discusses the results obtained using this numerical model for the prediction of the nonlinear absorbing media behaviour as well as how it affects the final double pulse combination. These results can be used to improve contrast cleaning conditions for high power laser chains and for synchronization studies, this last application was checked in the VEGA facility lab as a code validation.

scholarly journals Production of high contrast ultrashort laser pulses for short scale length plasma experiments

1994 ◽  
Author(s):  
W.E. White ◽  
A. Sullivan ◽  
D.F. Price ◽  
R. Trebino ◽  
K. DeLong ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
High Contrast ◽  
Short Scale ◽  
Ultrashort Laser ◽  
Scale Length

Plasma scale length and quantum electrodynamics effects on particle acceleration at extreme laser plasmas

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
Ozgur Culfa ◽  
Sinan Sagir
Keyword(s):  
Particle Acceleration ◽  
Quantum Electrodynamics ◽  
Charged Particles ◽  
Front Surface ◽  
Radiation Reaction ◽  
Maximum Energy ◽  
Particle In Cell ◽  
Qed Effects ◽  
Preformed Plasma ◽  
Scale Length

In this work, simulations of multipetawatt lasers at irradiances ${\sim }10^{23} \ \mathrm {W}\ \mathrm {cm}^{-2}$ , striking solid targets and implementing two-dimensional particle-in-cell code was used to study particle acceleration. Preformed plasma at the front surface of a solid target increases both the efficiency of particle acceleration and the reached maximum energy by the accelerated charged particles via nonlinear plasma processes. Here, we have investigated the preformed plasma scale length effects on particle acceleration in the presence and absence of nonlinear quantum electrodynamic (QED) effects, including quantum radiation reaction and multiphoton Breit–Wheeler pair production, which become important at irradiances ${\sim } 10^{23}\ \mathrm {W}\ \mathrm {cm}^{-2}$ . Our results show that QED effects help particles gain higher energies with the presence of preformed plasma. In the results for all cases, preplasma leads to more efficient laser absorption and produces more energetic charged particles, as expected. In the case where QED is included, however, physical mechanisms changed and generated secondary particles ( $\gamma$ -rays and positrons) reversing this trend. That is, the hot electrons cool down due to QED effects, while ions gain more energy due to different acceleration methods. It is found that more energetic $\gamma$ -rays and positrons are created with increasing scale length due to high laser conversion efficiency ( ${\sim }$ 24 % for $\gamma$ -rays and $\sim$ 4 % for positrons at $L = 7\ \mathrm {\mu }\textrm {m}$ scale length), which affects the ion and electron acceleration mechanisms. It is also observed that the QED effect reduces the collimation of angular distribution of accelerated ions because the dominant ion acceleration mechanism is changing when QED is involved in the process.

scholarly journals Influence of the initial size of the proton layer in sheath field proton acceleration

2013 ◽  
Vol 31 (4) ◽  
pp. 597-605 ◽  
Author(s):  
Jinqing Yu ◽  
Xiaolin Jin ◽  
Weimin Zhou ◽  
Bo Zhang ◽  
Zongqing Zhao ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Target Thickness ◽  
Energy Spread ◽  
Divergence Angle ◽  
Initial Size ◽  
Proton Acceleration ◽  
Particle In Cell ◽  
High Intensity Laser ◽  
Intensity Laser ◽  
Peak Value

AbstractWe investigate the influence of the initial size of the proton layer on proton acceleration in the interaction of high intensity laser pulses with double-layer targets by using two-dimensional particle-in-cell code. We discuss the influence of proton layer initial sizes on the cut-off energy, energy spread, and divergence angle of proton beam. It is found that Coulomb explosion plays an important role on the proton cut-off energy. This causes the cut-off energy to increase for increasing proton layer thickness, at the expense of energy spread. The proton divergence angle reaches a peak value and then falls again with increasing the width. Proton divergence angle grows with target thickness. It is found that there is an optimal thickness to obtain the narrowest energy spread, which may provide an effective method (change the size of proton layer) to obtain high quality proton beams. This work may serve to improve the understanding of sheath field proton acceleration.

scholarly journals Diagnostics of peak laser intensity based on the measurement of energy of electrons emitted from laser focal region

2015 ◽  
Vol 33 (3) ◽  
pp. 361-366 ◽  
Author(s):  
M. Kalashnikov ◽  
A. Andreev ◽  
K. Ivanov ◽  
A. Galkin ◽  
V. Korobkin ◽  
...  
Keyword(s):  
Laser Intensity ◽  
Laser Pulses ◽  
Maximum Energy ◽  
Beam Waist ◽  
Focal Region ◽  
Low Density ◽  
Particle In Cell ◽  
Peak Intensity ◽  
Low Density Plasma ◽  
Density Plasma

AbstractA new method to determine the peak intensity of focused relativistic laser pulses is experimentally justified. It is based on the measurement of spectra of electrons, accelerated in the beam waist. The detected electrons were emitted from the plasma, generated by nonlinear ionization of low-density gases (helium, argon, and krypton) in the focal area of a laser beam with the peak intensity >1020 W/cm2. The measurements revealed generation of particles with the maximum energy of a few MeV, observed at a small angle relative to the beam axis. The results are supported by numerical particle-in-cell simulations of a laser–low-density plasma interaction. The peak intensity in the focal region derived from experimental data reaches the value of 2.5 × 1020 W/cm2.

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