中国物理B ›› 2007, Vol. 16 ›› Issue (10): 3009-3015.doi: 10.1088/1009-1963/16/10/032

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Effect of sheath potential on electromagnetic radiation emitted from the rear surface of a metallic foil target

薮内俊毅1, 田中和夫1, 郑 坚2, 李志超2, 张 辉2, 俞昌旋2   

  1. (1)Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan; (2)Key Laboratory of Basic Plasma Physics, Chinese Academy of Sciences, Department of Modern Physics, University of Science and Technology of China, Hefei { 230026, China
  • 收稿日期:2007-01-04 修回日期:2007-04-16 出版日期:2007-10-08 发布日期:2007-10-08
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10575102, 10375064 and 10625523), State Key Laboratory of Plasma Physics (Grant No 51480010105ZK0101), Ministry of Education (NCET-04-0584), and China-Japan Core University P

Effect of sheath potential on electromagnetic radiation emitted from the rear surface of a metallic foil target

Zheng Jian(郑坚)a)†, Li Zhi-Chao(李志超)a), Zhang Hui(张辉)a), Yu Chang-Xuan(俞昌旋)a), Yabuuchi Toshinori(薮内俊毅)b), and Tanaka Kazuo(田中和夫)b)   

  1. a Key Laboratory of Basic Plasma Physics, Chinese Academy of Sciences, Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; b Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan
  • Received:2007-01-04 Revised:2007-04-16 Online:2007-10-08 Published:2007-10-08
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10575102, 10375064 and 10625523), State Key Laboratory of Plasma Physics (Grant No 51480010105ZK0101), Ministry of Education (NCET-04-0584), and China-Japan Core University P

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摘要： In ultra-intense laser--matter interactions, intense electric fields formed at the rear surface of a foil target may have strong influences on the motion of energetic electrons, and thereby affect the electromagnetic emissions from the rear surface, usually ascribed to transition radiation. Due to the electric fields, transition radiation occurs twice and bremsstrahlung radiation also happens because the electrons will cross the rear surface twice and have large accelerations. In the optic region, transition radiation is dominant. The radiation spectrum depends on the electric field only when the electrons are monochromatic, and becomes independent of the electric field when the electrons have a broadband momentum distribution. Therefore, in an actual experiment, the electric field at the rear surface of a foil could not be studied just with the measurement of optic emissions. In the terahertz region, both bremsstrahlung and transition radiations should be taken into account, and the radiation power could be enhanced in comparison with that without the inclusion of bremsstrahlung radiation. The frequency at which the maximum terahertz radiation appears depends on the electric field.

关键词: sheath potential, transition radiation, bremsstrahlung radiation, energetic electrons

Abstract: In ultra-intense laser--matter interactions, intense electric fields formed at the rear surface of a foil target may have strong influences on the motion of energetic electrons, and thereby affect the electromagnetic emissions from the rear surface, usually ascribed to transition radiation. Due to the electric fields, transition radiation occurs twice and bremsstrahlung radiation also happens because the electrons will cross the rear surface twice and have large accelerations. In the optic region, transition radiation is dominant. The radiation spectrum depends on the electric field only when the electrons are monochromatic, and becomes independent of the electric field when the electrons have a broadband momentum distribution. Therefore, in an actual experiment, the electric field at the rear surface of a foil could not be studied just with the measurement of optic emissions. In the terahertz region, both bremsstrahlung and transition radiations should be taken into account, and the radiation power could be enhanced in comparison with that without the inclusion of bremsstrahlung radiation. The frequency at which the maximum terahertz radiation appears depends on the electric field.

Key words: sheath potential, transition radiation, bremsstrahlung radiation, energetic electrons

中图分类号:  (Emission, absorption, and scattering of electromagnetic radiation ?)

  • 52.25.Os
52.38.Kd (Laser-plasma acceleration of electrons and ions) 52.70.Kz (Optical (ultraviolet, visible, infrared) measurements)