High energy electrons and x-ray photons emitted by water plasmas produced by femtosecond laser pulses

作     者：Y. T. Li, J. Zhang, Z. M. Sheng, H.Teng, T. J. Liang, X. Y. Peng, X. Lu, Y. J. Li, X. W. Tang Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, P. R. China Insitute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, P. R. China 

会议名称：《CCAST“2002年全国强场激光物理”研讨会》

会议日期：2002年

学科分类：080901[工学-物理电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0803[工学-光学工程] 

基　　金：This work was supported by the NNSFC (Project Numbers: 19974074, 10204023, 10075075, 10105014, 10176034 and 19845110) the K. C. Wang Education Foundation (Hong Kong) the National High-Tech ICF program the NKBRSF (Grant No. G1 99990-75200) 

摘      要：正Hot electrons and x-ray photons emitted by water plasmas produced by single and multiple laser pulses are investigated. For the same pulse energy of 5 mJ in our experiments, the multipulse mode greatly enhances the generation of hot electrons. The hot-electron temperature is about 64 keV, and electrons with energies higher than 25 keV are emitted in two directions symmetrically at 46?from the direction of the laser electric field and in the polarization plane. Two-dimensional particle-in-cell simulations reproduce well the experimental results and indicate that the acceleration mechanism of hot electrons is mainly due to the resonance absorption at the edge of the spherical droplets formed by leading pulses.