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Title: Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme

Abstract

A scheme of using two-color laser pulses for hole boring into overdense plasma as well as energy transfer into electron and ion beams has been studied using particle-in-cell simulations. Following an ultra-short ultra-intense hole-boring laser pulse with a short central wavelength in extreme ultra-violet range, the main infrared driving laser pulse can be guided in the hollow channel preformed by the former laser and propagate much deeper into an overdense plasma, as compared to the case using the infrared laser only. In addition to efficiently transferring the main driving laser energy into energetic electrons and ions generation deep inside the overdense plasma, the ion beam divergence can be greatly reduced. The results might be beneficial for the fast ignition concept of inertial confinement fusion.

Authors:
; ; ; ; ; ;  [1];  [2];  [1];  [3]
  1. State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)
  2. Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)
  3. (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240 (China)
Publication Date:
OSTI Identifier:
22599859
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COLOR; COMPARATIVE EVALUATIONS; ENERGY TRANSFER; HOLES; INERTIAL CONFINEMENT; ION BEAMS; LASERS; PARTICLES; PLASMA; PULSES; RELATIVISTIC RANGE; SIMULATION; TAIL ELECTRONS; THERMONUCLEAR IGNITION; WAVELENGTHS

Citation Formats

Yu, Changhai, Tian, Ye, Li, Wentao, Wang, Wentao, Zhang, Zhijun, Qi, Rong, Wang, Cheng, Deng, Aihua, E-mail: aihuadeng1985@gmail.com, Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn, and Collaborative Innovation Center of IFSA. Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme. United States: N. p., 2016. Web. doi:10.1063/1.4960036.
Yu, Changhai, Tian, Ye, Li, Wentao, Wang, Wentao, Zhang, Zhijun, Qi, Rong, Wang, Cheng, Deng, Aihua, E-mail: aihuadeng1985@gmail.com, Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn, & Collaborative Innovation Center of IFSA. Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme. United States. doi:10.1063/1.4960036.
Yu, Changhai, Tian, Ye, Li, Wentao, Wang, Wentao, Zhang, Zhijun, Qi, Rong, Wang, Cheng, Deng, Aihua, E-mail: aihuadeng1985@gmail.com, Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn, and Collaborative Innovation Center of IFSA. Mon . "Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme". United States. doi:10.1063/1.4960036.
@article{osti_22599859,
title = {Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme},
author = {Yu, Changhai and Tian, Ye and Li, Wentao and Wang, Wentao and Zhang, Zhijun and Qi, Rong and Wang, Cheng and Deng, Aihua, E-mail: aihuadeng1985@gmail.com and Liu, Jiansheng, E-mail: michaeljs-liu@siom.ac.cn and Collaborative Innovation Center of IFSA},
abstractNote = {A scheme of using two-color laser pulses for hole boring into overdense plasma as well as energy transfer into electron and ion beams has been studied using particle-in-cell simulations. Following an ultra-short ultra-intense hole-boring laser pulse with a short central wavelength in extreme ultra-violet range, the main infrared driving laser pulse can be guided in the hollow channel preformed by the former laser and propagate much deeper into an overdense plasma, as compared to the case using the infrared laser only. In addition to efficiently transferring the main driving laser energy into energetic electrons and ions generation deep inside the overdense plasma, the ion beam divergence can be greatly reduced. The results might be beneficial for the fast ignition concept of inertial confinement fusion.},
doi = {10.1063/1.4960036},
journal = {Physics of Plasmas},
number = 8,
volume = 23,
place = {United States},
year = {Mon Aug 15 00:00:00 EDT 2016},
month = {Mon Aug 15 00:00:00 EDT 2016}
}
  • Recently achieved high intensities of short laser pulses open new prospects in their application to hole boring in inhomogeneous overdense plasmas and for ignition in precompressed DT fusion targets. A simple analytical model and numerical simulations demonstrate that pulses with intensities exceeding 10{sup 22} W/cm{sup 2} may penetrate deeply into the plasma as a result of efficient ponderomotive acceleration of ions in the forward direction. The penetration depth as big as hundreds of microns depends on the laser fluence, which has to exceed a few tens of GJ/cm{sup 2}. The fast ions, accelerated at the bottom of the channel withmore » an efficiency of more than 20%, show a high directionality and may heat the precompressed target core to fusion conditions.« less
  • Laser hole boring and relativistic electron transport into plasma of 10 times critical density is studied by means of 2D particle-in-cell simulation. At intensities of I{sub 0}{lambda}{sup 2}=10{sup 20} W(cm){sup {minus}2} {mu}m{sup 2}, a channel 12{lambda} deep and 3{lambda} in diameter has formed after 200 laser cycles. The laser driven electron current carries up to 40{percent} of the incident laser power. When penetrating the overdense region, it breaks up into several filaments at early times, but is channeled into a single magnetized jet later on. These features are essential for fast ignition of targets for inertial confinement fusion (ICF). {copyright}more » {ital 1997} {ital The American Physical Society}« less
  • It is shown that well collimated mono-energetic ion beams with a large particle number can be generated in the hole-boring radiation pressure acceleration regime by using an elliptically polarized laser pulse with appropriate theoretically determined laser polarization ratio. Due to the J Multiplication-Sign B effect, the double-layer charge separation region is imbued with hot electrons that prevent ion pileup, thus suppressing the double-layer oscillations. The proposed mechanism is well confirmed by Particle-in-Cell simulations, and after suppressing the longitudinal double-layer oscillations, the ion beams driven by the elliptically polarized lasers own much better energy spectrum than those by circularly polarized lasers.
  • It is proposed that laser hole-boring at a steady speed in inhomogeneous overdense plasma can be realized by the use of temporally tailored intense laser pulses, producing high-fluence quasi-monoenergetic ion beams. A general temporal profile of such laser pulses is formulated for arbitrary plasma density distribution. As an example, for a precompressed deuterium-tritium fusion target with an exponentially increasing density profile, its matched laser profile for steady hole-boring is given theoretically and verified numerically by particle-in-cell simulations. Furthermore, we propose to achieve fast ignition by the in-situ hole-boring accelerated ions using a tailored laser pulse. Simulations show that the effectivemore » energy fluence, conversion efficiency, energy spread, and collimation of the resulting ion beam can be significantly improved as compared to those found with un-tailored laser profiles. For the fusion fuel with an areal density of 1.5 g cm{sup –2}, simulation indicates that it is promising to realize fast ion ignition by using a tailored driver pulse with energy about 65 kJ.« less
  • Thin, mass-limited targets composed of V/Cu/Al layers with diameters ranging from 50 to 300 {mu}m have been isochorically heated by a 300 fs laser pulse delivering up to 10 J at 2x10{sup 19} W/cm{sup 2} irradiance. Detailed spectral analysis of the Cu x-ray emission indicates that the highest temperatures, of the order of 100 eV, have been reached when irradiating the smallest targets with a high-contrast, frequency-doubled pulse despite a reduced laser energy. Collisional particle-in-cell simulations confirm the detrimental influence of the preformed plasma on the bulk target heating.