关键词：
wave-particle interaction;acceleration of energetic electrons;whistler-mode chorus;latitudinal distribution
摘要：
Primary result on the impact of the latitudinal distribution of whistler-mode chorus upon temporal evolution of the phase space density (PSD) of outer radiation belt energetic electrons was presented.We evaluate diffusion rates in pitch angle and momentum due to a band of chorus frequency distributed at a standard Gaussian spectrum,and solve a 2-D bounce-averaged momentum-pitch-angle Fokker-Planck equation at L=4.5.It is shown that chorus is effective in accelerating electrons and can increase PSD for energy of ～1 MeV by a factor of 10 or more in about one day,which is consistent with observation.Moreover,the latitudinal distribution of chorus has a great impact on the acceleration of electrons.As the latitudinal distribution increases,the efficient acceleration region extends from higher pitch angles to lower pitch angles,and even covers the entire pitch angle region when chorus power reaches the maximum latitude λm=45°.
关键词：
Squeezed atom laser;Bose-Einstein condensation;Stimulated Raman transition
摘要：
We present a scheme to generate a squeezed atom laser via stimulated Raman transition of the atoms in Bose–Einstein condensate (BEC) interacting with two light beams, including a weaker squeezed coherent probe light and a stronger classical pump light. The results show that the quantum fluctuation of this atom laser can be periodically squeezed. The squeezing depth of such atom laser is determined by the initial squeezing factor of the probe light, and the squeezing period of that is related to the mean number of atoms in the trap, the strength of interaction between squeezing light and BEC atoms, and the detuning of the light.
作者机构：
[Peng, Runwu; Tang, Lijun] Department of Physics and Electronic Science, Changsha University of Science and Technology, Changsha, Hunan 410076, China;[Peng, Qinjun; Li, Fangqin; Cui, Qianjin; Cui, Dafu; Zhang, Xiaofu; Guo, Lin; Peng, Runwu; Bo, Yong; Xu, Zuyan] Laboratory of Optical Physics, Institute of Physics, Chinese Acad. of Sci., Beijing 100080, China
通讯机构：
Department of Physics and Electronic Science, Changsha University of Science and Technology, China
摘要：
A high average power and high beam quality picosecond laser system combined with diode-end-pumped Nd:YVO<inf>4</inf> and laser diode-side-pumped Nd:YAG amplifier is described. The system combines the advantages of Nd:YVO<inf>4</inf> crystal having large stimulated-emission cross section and Nd:YAG crystal having good thermal conductivity. The diode-end-pumped Nd:YVO<inf>4</inf> amplifier allows the laser from the oscillator to obtain high gain so that the laser can amplify rapidly and the diode-side-pumped Nd:YAG amplifier benefits to obtain high output power. The Nd:YAG amplifier is designed as double-pass form to increase the efficiency of the amplifier. Spatial filters are adopted between amplifiers to ensure good beam quality and mode matching. Picosecond laser with average power of 43.4 W and good beam quality factor M<sup>2</sup><1.7 is generated from this laser system.
摘要：
Observation has clearly shown that natural space plasmas generally possess a pronounced non-Maxwellian high-energy tail distribution that can be well modeled by a kappa distribution. In this study we investigate the proton cyclotron wave instability driven by the temperature anisotropy (T-perpendicular to/T-parallel to>1) of suprathermal protons modeled with a typical kappa distribution in the magnetosheath. It is found that as in the case for a regular bi-Maxwellian, the suprathermal proton temperature anisotropy is subject to the threshold condition of this proton cyclotron instability and the instability threshold condition satisfies a general form T-perpendicular to/T-parallel to - 1 = S/beta(alpha)(parallel to), with a very narrow range of the fitting parameters: 0.40 less than or similar to alpha less than or similar to 0.45, and a relatively sensitive variation 0.27 less than or similar to S less than or similar to 0.65, over 0.01 <= beta(parallel to) <= 10. Furthermore, the difference in threshold conditions between the kappa distribution and the bi-Maxwellian distribution is found to be small for a relatively strong growth but becomes relatively obvious for a weak wave growth. The results may provide a deeper insight into the physics of this instability threshold for the proton cyclotron waves.
摘要：
This paper discusses the physics of the anti-matter world, extends the meaning of supercharge and applied scope of the Gell-Mann-Nishijima formula, give out features of all antiquark quantum numbers,describes the interaction in the antimatter world, explores the forming condition of antimatter and the existence of cosmic antimatter, points out some antimatter-celestial bodies still possible existence, and that both the matter and anti-matter have identical interaction field, alike atomic energy level structure and similar spectrum, nowaday observational methods can not distinguish celestial body and antibody.
作者机构：
[杨介甫] Dept. of Physics of Science College, Hunan Normal University, Changsha 410081, China;[陈笑梅] Editorial Department, Hunan Normal University, Changsha 410081, China;[唐立军] Department of Physics, Changsha Univ. of Electric Power, Changsha 410007, China;[陈瑞凯] Materials Science Center, Taiwan Qinghua University, Xinzhu 30043, China
