scholarly journals Generation and transport of fast electrons inside cone targets irradiated by intense laser pulses

2006 ◽  
Vol 24 (1) ◽  
pp. 5-8 ◽  
Author(s):  
TATSUFUMI NAKAMURA ◽  
HITOSHI SAKAGAMI ◽  
TOMOYUKI JOHZAKI ◽  
HIDEO NAGATOMO ◽  
KUNIOKI MIMA
Keyword(s):  
Laser Pulses ◽  
Transport Processes ◽  
Hot Electrons ◽  
Intense Laser ◽  
Rear Side ◽  
Fast Electrons ◽  
Surface Magnetic Field ◽  
Particle In Cell ◽  
Intense Laser Pulses ◽  
Cone Target

Fast electrons are effectively generated from solid targets of cone-geometry by irradiating intense laser pulses, which is applied to fast ignition scheme. For realizing optimal core heating by those electrons, understanding the characteristics of electrons emitted from cone targets is crucial. In this paper, in order to understand the generation and transport processes of hot electrons inside the cone target, two-dimensional (2D) particle-in-cell (PIC) simulations were carried out. It is shown that hot electrons form current layers which are guided by self-generated surface magnetic field, which results in effective energy transfer from laser pulse to hot electrons. When the hot electrons propagate through the steep density gradient at the cone tip, electrostatic field is induced via Weibel instability. As a result, hot electrons are confined inside and emitted gradually from the target, as an electron beam of long duration. Energy spectrum and temporal profile of hot electrons are also evaluated at the rear side of the target, where the profile of rear side plasma is taken from the fluid code and the result is sent to Fokker-Planck code.

Collimation of laser-driven energetic protons in a capillary

2012 ◽  
Vol 78 (4) ◽  
pp. 333-337
Author(s):  
D.-P. CHEN ◽  
Y. YIN ◽  
Z.-Y. GE ◽  
H. XU ◽  
H.-B. ZHUO ◽  
...  
Keyword(s):  
Proton Beam ◽  
Electron Flow ◽  
Laser Pulses ◽  
Hot Electrons ◽  
Beam Divergence ◽  
Intense Laser ◽  
Particle In Cell ◽  
Intense Laser Pulses ◽  
Electric And Magnetic Fields ◽  
Set Up

AbstractEnergetic divergent proton beams can be generated in the interaction of ultra-intense laser pulses with solid-density foil targets via target normal sheath acceleration (TNSA). In this paper, a scheme using a capillary to reduce the proton beam divergence is proposed. By two-dimensional particle-in-cell (PIC) simulations, it is shown that strong transverse electric and magnetic fields rapidly grow at the inner surface of the capillary when the laser-driven hot electrons propagate through the target and into the capillary. The spontaneous magnetic field collimates the electron flow, and the ions dragged from the capillary wall by hot electrons neutralize the negative charge and thus restrain the transverse extension of the sheath field set up by electrons. The proton beam divergence, which is mainly determined by the accelerating sheath field, is therefore reduced by the transverse limitation of the sheath field in the capillary.

Application of encapsulated hollow Gold nanocluster targets for high-quality and quasi-monoenergetic ions generation

2021 ◽  
Author(s):  
Mahsa Mehrangiz
Keyword(s):  
Gold Cluster ◽  
Laser Pulses ◽  
Intense Laser ◽  
Hollow Nanosphere ◽  
High Quality ◽  
Gold Nanocluster ◽  
Particle In Cell ◽  
Intense Laser Pulses ◽  
Void Area ◽  
Simulation Results

Abstract With persistent progress in ultra-intense laser pulses, Coulomb explosion (CE) of spherical nanoclusters can in principle produce high-quality-quasi-monoenergetic ions. Focusing on using CE framework, in this paper, we have proposed a target scheme to accelerate light/heavy ions’ beam. The scheme relies on encapsulating a hollow Gold nanocluster inside a hollow proton-Carbon (HC) nanosphere. The ability of this suggestion has been simulated by the two-dimensional particle-in-cell code (EPOCH). Simulation results exhibit that a hollow Gold cluster can positively increase the electrons’ extraction. This condition may improve the acceleration of low-divergence H+, C6+, and Au67+ ions. Our simulation shows that at the end of the interaction, for a Gold cluster with an optimal hollow radius of 91.3 nm, the cut-off energy of H+, C6+, and Au67+ are about 54.9 MeV/u, 51.5 MeV/u, and 54.9 MeV/u, respectively. In this case, an increase of about 52% for H+ and 61% for C6+ is obtained, contrast to bare HC hollow nanosphere (i.e., a hollow nanosphere with no cluster), while the relative divergence decreases to 1.38 and 1.86, respectively for H+ and C6+ ions. We have also compared our simulation results with another proposed target structure composed of a void area with an optimum diameter of 70.4 nm between the fully- Gold nanocluster and HC nanosphere. We have exhibited that the results are improved, contrast to bare nanosphere. However, the cut-off energy suppression and angular divergence increase are shown compared with encapsulated hollow Gold nanocluster structure.

scholarly journals Hot electron refluxing in the short intense laser pulse interactions with solid targets and its influence on K-α radiation

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Vojtěch Horný ◽  
Ondřej Klimo
Keyword(s):  
Strong Electric Field ◽  
Target Material ◽  
Target Thickness ◽  
Intense Laser ◽  
Rear Side ◽  
Hot Electron ◽  
Fast Electrons ◽  
X Ray ◽  
Particle In Cell ◽  
Beam Interaction

Abstract Fast electrons created as a result of the laser beam interaction with a solid target penetrate into the target material and initialize processes leading to the generation of the characteristic X-ray K-α radiation. Due to the strong electric field induced at the rear side of a thin target the transmitted electrons are redirected back into the target. These refluxing electrons increase the K-α radiation yield, as well as the duration of the X-ray pulse and the size of the radiation emitting area. A model describing the electron refluxing was verified via particle-in-cell simulations for non-relativistic electron energies. Using this model it was confirmed that the effect of the electron refluxing on the generated X-ray radiation depends on the target thickness and the target material. A considarable increase of the number of the emitted K-α photons is observed especially for thin targets made of low-Z materials, and for higher hot electron temperatures.

scholarly journals Simulations of energetic proton emission in laser–plasma interaction

2003 ◽  
Vol 21 (4) ◽  
pp. 573-581 ◽  
Author(s):  
LAURENT POMMIER ◽  
ERIK LEFEBVRE
Keyword(s):  
Laser Pulses ◽  
Hot Electrons ◽  
Rear Side ◽  
Laser Irradiance ◽  
Laser Plasma Interaction ◽  
Particle In Cell ◽  
Thin Foils ◽  
Short Laser Pulses ◽  
Additional Support ◽  
Density Scale

Energetic protons are emitted from thin foils irradiated by short laser pulses at high intensities. One- and two-dimensional particle-in-cell simulations have been used to study the influence of initial proton position, laser irradiance, and target density profile on this ion acceleration. These simulations bring additional support to the idea that protons are mainly accelerated from the rear side of the target, by electrostatic fields associated with hot electrons escaping into vacuum. The density scale length at the front of the target appears to be the main parameter to increase proton energies when the laser irradiance is fixed.

Towards Sub-TeV electron beams driven by ultra-short, ultra-intense laser pulses

2012 ◽  
Vol 78 (4) ◽  
pp. 461-468 ◽  
Author(s):  
WEI-MIN WANG ◽  
ZHENG-MING SHENG ◽  
SHIGEO KAWATA ◽  
CHUN-YANG ZHENG ◽  
YU-TONG LI ◽  
...  
Keyword(s):  
Laser Intensity ◽  
Electron Beams ◽  
Energetic Electron ◽  
Thin Foil ◽  
Laser Pulses ◽  
Intense Laser ◽  
Particle In Cell ◽  
Intense Laser Pulses ◽  
Laser Focus ◽  
Foil Target

AbstractEnergetic electron beam generation from a thin foil target by the ponderomotive force of an ultra-intense circularly polarized laser pulse is investigated. Two-dimensional particle-in-cell (PIC) simulations show that laser pulses with intensity of 1022–1023 Wcm−2 generate about 1–10 GeV electron beams, in agreement with the prediction of one-dimensional theory. When the laser intensity is at 1024–1025 Wcm−2, the beam energy obtained from PIC simulations is lower than the values predicted by the theory. The radiation damping effect is considered, which is found to become important for the laser intensity higher than 1025 Wcm−2. The effect of laser focus positions is also discussed.

Efficient generation of proton bunches by intense laser pulse with a double-slice-foil target

2012 ◽  
Vol 78 (4) ◽  
pp. 491-496
Author(s):  
JUN ZHENG ◽  
ZHENG-MING SHENG ◽  
JIN-LU LIU ◽  
WEI-MIN ZHOU ◽  
HAN XU ◽  
...  
Keyword(s):  
Double Layer ◽  
Laser Pulses ◽  
Intense Laser ◽  
Particle In Cell ◽  
Intense Laser Pulses ◽  
Proton Beam Energy ◽  
Direct Laser ◽  
Laser Acceleration ◽  
Foil Target ◽  
Target Design

AbstractA double-slice-foil target is proposed for the generation of quasi-monoenergetic proton bunches by intense laser pulses. In this new target structure, two symmetrical solid slices are adjoined obliquely to the front side of a plane double-layer target. Two-dimensional particle-in-cell simulations show that a large number of hot electrons are pulled out from solid slices and accelerated forward by direct laser acceleration, which lead to significant enhancement of the sheath field and the produced proton beam energy as compared with the normal plane double-layer target and some other modified targets. It appears that well-collimated proton bunches with energy larger than 200 MeV can be produced at the focused laser intensity of about 1021W/cm2 with the proposed target design.

scholarly journals Influence of laser incidence angle on hot electrons generated in the interaction of ultrashort intense laser pulses with foil target

2006 ◽  
Vol 55 (11) ◽  
pp. 5899
Author(s):  
Yuan Xiao-Hui ◽  
Li Yu-Tong ◽  
Xu Miao-Hua ◽  
Zheng Zhi-Yuan ◽  
Liang Wen-Xi ◽  
...  
Keyword(s):  
Incidence Angle ◽  
Laser Pulses ◽  
Hot Electrons ◽  
Intense Laser ◽  
Intense Laser Pulses ◽  
Foil Target

scholarly journals Efficient acceleration of a small dense plasma pellet by consecutive action of multiple short intense laser pulses

2009 ◽  
Vol 27 (4) ◽  
pp. 629-634 ◽  
Author(s):  
X. Wang ◽  
W. Yu ◽  
M.Y. Yu ◽  
V.K. Senecha ◽  
H. Xu ◽  
...  
Keyword(s):  
Dense Plasma ◽  
Ponderomotive Force ◽  
Laser Pulses ◽  
Intense Laser ◽  
Energetic Ions ◽  
Practical Applications ◽  
Particle In Cell ◽  
High Speeds ◽  
Intense Laser Pulses ◽  
Cell Simulation

AbstractThe acceleration of a micrometer-sized plasma pellet at 100 critical densities (1023 cm−3) by consecutive application of ultra-short ultra-intense laser pulses is studied using two-dimensional particle-in-cell simulation. It is shown that due to the repeated actions of the laser ponderomotive force, a small dense plasma pellet can be efficiently accelerated, with a considerable fraction of the plasma ions accelerated to high speeds. The proposed scheme can provide a high-density flux of energetic ions, which should be valuable in many practical applications.

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