摘要
激光加速是近年提出的一种新型加速机制,它以等离子体为加速介质,受到等离子体性质的强烈影响.电离毛细管装置作为一种能稳定产生等离子体通道和调制等离子体参数的可靠工具,既可以承载激光等离子体尾波的高梯度加速场,又能提供放电电流驱动的高梯度横向聚焦磁场,在紧凑型激光加速器、辐射源及等离子体透镜的研究中发挥着重要作用.本文介绍了电离毛细管等离子体的原理及特性,归纳了它在激光加速领域的主要应用,包括作为加速段进一步提高激光等离子体加速粒子束的能量及质量、作为束流传输元件匹配加速粒子束的实际应用需求.在此基础上,对毛细管等离子体未来的发展趋势进行了展望,并简要介绍了北京大学电离毛细管等离子体平台的建设情况.
Laser acceleration is a new type of acceleration mechanism proposed in recent years.It uses plasma as the acceleration medium so it is strongly affected by the properties of plasma.Laser acceleration can achieve acceleration gradients that are three orders of magnitude higher than those obtained by conventional accelerators,which makes it a strong contender for the construction of future compact high energy particle accelerators and radiation sources.However,high gradient and transient acceleration also lead to low energy conversion efficiency and instability of laser acceleration,which are challenges that must be overcome in this field.On one hand,in the absence of guidance,the focused laser beam will diverge rapidly and maintain high intensity only in a short distance,which greatly limits the energy of the accelerated particles;on the other hand,the laser-accelerated particle beam has the characteristics of wide energy spectrum and large divergence angle.In order to meet the requirements of practical applications,it is necessary to use focusing elements to collect and focus the particle beam.At the same time,in order to demonstrate the advantage of high acceleration gradient of laser accelerators,corresponding compact beam focusing devices must be matched.Tailoring and controlling the properties of plasma is essential for the accurate design,operation and application of laser plasma accelerators.As a reliable tool for stably generating plasma channels and modulating plasma parameters,capillary discharge can provide solutions to these problems above-mentioned.The capillary discharge is often described as a cmlong,gas-filled,elongated chamber with an mm-diameter circular cross section implanted in a sapphire or glass block.The plasma is generated in the capillary by an electrical discharge current between two electrodes at the ends,and the plasma’s parameters,such as the density and temperature,can be easily adjusted by changing the geometric structure of the capillary,the gas pressure,and the current setting.The capillary discharge plasma can not only carry the high-gradient acceleration field of the laser plasma wake,but also provide the high-gradient transverse focusing magnetic field driven by the discharge current,which makes it widely used in the field of laser acceleration.Combining high-gradient acceleration fields with high-gradient transmission fields using plasma technology,compact table-top laser accelerators are expected to be truly realized.This review introduces the working principle and characteristics of capillary discharge plasma,and summarizes its main applications in the field of laser acceleration:As an acceleration section,it can extend the acceleration distance and further improve the energy and quality of laser plasma accelerated particle beams;as a beam transmission element,it can achieve axisymmetric focusing on the scale of centimeters to tens of centimeters to increase the cluster density and improve the practical application level of laser accelerated particle beams.On the basis of summarizing the existing research progress,the future development trend of capillary plasma is prospected,and the construction of the capillary discharge plasma platform of Peking University is briefly introduced.
作者
晏炀
杨童
郭臻
程浩
李昱泽
方言律
夏亚东
何强友
李辰童
林晨
颜学庆
Yang Yan;Tong Yang;Zhen Guo;Hao Cheng;Yuze Li;YanlüFang;Yadong Xia;Qiangyou He;Chentong Li;Chen Lin;Xueqing Yan(State Key Laboratory of Nuclear Physics and Technology,Peking University,Beijing 100871,China;Beijing Laser Acceleration Innovation Center,Beijing 101407,China;Institute of Guangdong Laser Plasma Technology,Guangzhou 510475,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2023年第16期2058-2069,共12页
Chinese Science Bulletin
基金
国家自然科学基金(11975037,6163101001,11921006)
国家重大科研仪器研制项目(2019YFF01014400,2019YFF01014404)资助。
关键词
电离毛细管
等离子体
激光加速
高梯度
capillary discharge
plasma
laser acceleration
high gradient
