中国物理B ›› 2007, Vol. 16 ›› Issue (10): 3009-3015.doi: 10.1088/1009-1963/16/10/032
薮内俊毅1, 田中和夫1, 郑 坚2, 李志超2, 张 辉2, 俞昌旋2
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)
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.
中图分类号: (Emission, absorption, and scattering of electromagnetic radiation ?)