强激光驱动的梯度靶等离子块加速

doi:10.3969/j.issn.1000-5641.2025.03.011

摘要/Abstract

摘要：

通过粒子(particle-in-cell, PIC)模拟技术, 提出了一种强激光 ($ {I}_{0} $ ~ 10¹⁸ W/cm²) 驱动的基于非对称内爆的梯度靶等离子体块加速新方案. 以质子靶为例, 首先给出均匀密度靶中等离子体内爆的特征, 以及靶厚、激光极化和脉冲长度等参数对内爆的影响; 在此基础上, 通过改变靶的密度梯度, 破坏引发内爆的有质动力势的对称性, 形成等离子体的非对称内爆. 与均匀密度靶中的对称内爆相比, 基于密度梯度靶的非对称内爆得到的等离子体块中的质子能量更高 (从10 keV量级提升到10² keV量级), 束流品质更好. 由于改进的质子能量正好处于质子-硼发生聚变反应的最大概率所在能区, 因此这一研究对于利用强激光驱动质子-硼聚变的方案有着重要的潜在应用价值.

关键词: 等离子体块加速, 强激光, 等离子体内爆, 质子-硼聚变, 粒子模拟

Abstract:

A new scheme of plasma block acceleration driven by intense lasers ($I_0 $ ~ 10¹⁸ W/cm²) is proposed based upon asymmetric plasma implosion in density gradient targets, using a particle-in-cell (PIC) simulation technique. Taking the proton target as an example, first, we present the implosion characteristics when the target has a homogeneous density. The influence of target thickness, laser polarization, and pulse length upon implosion are discussed. Then by changing the density gradient of the target, the asymmetric implosion induced by the asymmetric ponderomotive is investigated. Compared with the results from those based upon a target with homogenous density, the accelerated protons have higher energy, which is increased from magnitude of 10 keV to hundreds of keV, and the beam quality is also improved. Because the improved proton energy is just in the energy range for proton-boron fusion reactions with high probability, the above investigations would have great potential application for laser-driven proton-boron fusion research.

Key words: plasma block acceleration, intense laser, plasma implosion, proton-boron fusion, particle-in-cell simulation

中图分类号:

O437

黄渊凌, 王加祥. 强激光驱动的梯度靶等离子块加速[J]. 华东师范大学学报（自然科学版）, 2025, 2025(3): 90-99.

Yuanling HUANG, Jiaxiang WANG. Plasma block acceleration in density gradient targets driven by intense laser[J]. J* E* C* N* U* N* S*, 2025, 2025(3): 90-99.

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参考文献 14

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参数	取值	参数	取值
$ \lambda $	$ 100\;\mathrm{n}\mathrm{m} $	$ {n}_{0} $	$ 1{n}_{\mathrm{c}} $
$ {I}_{0} $	$ {1.6\times 10}^{18}\;\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2} $	$ d $	$ 360\;\mathrm{n}\mathrm{m} $
$ \tau $	$ 40\;\mathrm{f}\mathrm{s} $	polarization	CP

参数	取值	参数	取值
$ \lambda $	$ 100\;\mathrm{n}\mathrm{m} $	$ {n}_{0} $	$ 1{n}_{\mathrm{c}} $
$ {I}_{0} $	$ {1.6\times 10}^{18}\;\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2} $	$ d $	$ 200,\mathrm{ }\mathrm{400,600}\;\mathrm{n}\mathrm{m} $
$ \tau $	$ 40\;\mathrm{f}\mathrm{s} $	polarization	CP

参数	取值	参数	取值
$ \lambda $	$ 400\;\mathrm{n}\mathrm{m} $	$ {n}_{0} $	$1{n}_{\rm{c}}$
$ {I}_{0} $	$ {1.6\times 10}^{18}\;\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2} $	$ d $	$200,400\;\mathrm{n}\mathrm{m}$
$ \tau $	$ 40\;\mathrm{f}\mathrm{s} $	polarization	CP

参数	取值	参数	取值
$ \lambda $	$ 400\;{\mathrm{nm}} $	$ {n}_{0} $	$2{n}_{\rm{c}}$
$ {I}_{0} $	$ {1.6\times 10}^{18}\;{\mathrm{W}}/{{\mathrm{cm}}}^{2} $	$ d $	$ 400\;{\mathrm{nm}} $
$ \tau $	$ 40\;{\mathrm{fs}} $	polarization	CP