共查询到18条相似文献,搜索用时 78 毫秒
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共振、混沌与束晕形成 总被引:3,自引:0,他引:3
研究强流束中的非线性共振、混沌与束晕形成的关系.给出强流束中非线性共振范围的表达式及其随束流空间电荷效应变化的数值结果和图表曲线,提出由非线性共振而激发的束晕形成的空间电荷效应极限,并分析束晕形成的过程. 相似文献
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周期聚焦磁场中束晕-混沌的简单函数控制 总被引:1,自引:0,他引:1
本文采用粒子-束核模型,基于束晕-混沌的非线性控制策略,对周期性聚焦磁场中满足K—V分布的离子束进行模拟研究,提出了控制其束晕-混沌的简单函数控制器,并给出具体的实施方案.数值模拟研究表明,运用这种方法可以消除束晕及其再生现象,达到对束晕-混沌的有效控制. 相似文献
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运用PIC程序研究了强流离子束中粒子的横向运动,发现了不加控制时束晕粒子并非一直处于晕区和施加非线性控制后粒子的横向运动被限制在一定的范围内形成环状,以及均方根半径的变化近似成为周期运动等性质.根据观察到的均方根半径及其变化率的规律性,提出了一种新的自适应控制器.用该控制器不仅能在很短的时间内完全控制住束晕,而且不需要对增益因子进行精确计算,也能在系统参数改变的情况下取得较好的控制效果.
关键词:
束晕_混沌
粒子跟踪
数值模拟
自适应控制 相似文献
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回旋加速器中的空间电荷效应和束晕 总被引:2,自引:0,他引:2
在考虑束团内粒子之间的空间电荷相互作用力的条件下,对日本理化研究所(RIKEN)现有的一台注入器(加速常数为K70的AVF型回旋加速器)中束团的演变过程进行了模拟计算.模拟结果表明,束团的形变、束晕现象同样发生在回旋加速器中,不过,其产生机制不同于直线加速器.它不是由共振和混沌引起,而是由于粒子的排斥运动和束团内粒子的涡流运动引起的. 相似文献
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Momentum Distribution of a Fragment and Nucleon Removal Cross Section in the Reaction of Halo Nuclei
Recently the research on the halo structure of drip-line nuclei has shown some interesting properties of the existence of one or more halo nucleons. In the framework of few-body Glauber model, the momentum distribution of a fragment and nucleon removal cross section in the reaction of halo nuclei is presented and extended to nuclei having more than one halo nucleons. The reaction mechanism is treated with and without taking account of the final-state interaction. The wave function of removal halo nucleons in the continuum state is modified by imposing an orthogonal condition to the bound state. An analytical expression of the longitudinal momentum distribution of the fragment is derived when the bound state wave function of halo nucleons is taken as a Gaussian-type function. This is useful in the further investigation on the structure of halo nuclei. 相似文献
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Momentum Distribution of a Fragment and Nucleon Removal Cross
Section in the Reaction of Halo Nuclei
ZHAOYao-Lin MAZhong-Yu CHENBao-Qiu 《理论物理通讯》2003,40(6):693-698
Recently the research on the halo structure of drip-line nuclei has shown some interesting properties of the existence of one or more halo nucleons. In the framework of few-body Glauber model, the momentum distribution of a fragment and nucleon removal cross section in the reaction of halo nuclei is presented and extended to nuclei having more than one halo nucleons. The reaction mechanism is treated with and without taking account of the final-state interaction. The wave function of removal halo nucleons in the continuum state is modified by imposing an orthogonal condition to the bound state. An analytical expression of the longitudinal momentum distribution of the fragment is derived when the bound state wave function of halo nucleons is taken as a Gaussian-type function. This is useful in the further investigation on the structure of halo nuclei. 相似文献
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用薄透镜近似空间电荷相互作用的方法研究了强束流在周期场中的传输特性.通过计算可以说明束晕的形成.同时,也为研究比K–V分布更为复杂、真实的束流分布的传输特性提供了一种新的计算方法. 相似文献
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用非线性相对论平均场对两对镜像核13N-13C 和15N-15O进行了研究. 发现无论在基态还是激发态, 用两套参数所得的结合能都跟实验值很接近. 计算结果显示13N的第一激发态(2s1/2)和第三激发态(1d5/2)各存在一个非束缚的质子晕, 而13C的第三激发态(1d5/2)存在一个弱束缚的中子皮. 另外研究表明, 在另一对镜像核15N-15O的第二激发态(2s1/2)和第一激发态(2s1/2)分别存在一个中子晕和质子皮. Properties of two pairs of mirror nuclei 13N-13C and15N-15O are investigated by using the nonlinear relativistic mean field theory. It is found that all the calculated binding energies with two different parameter sets are very close to the experimental ones for both the ground states and the excited states. The calculations show that the first excited state (2s1/2) and the third excited state (1d5/2) in 13N are both unbound resonances with proton halo structure, whereas the third excited state (1d5/2) in 13C is weakly bound with a neutron skin. It is also predicted that there has a proton halo in the second excited state (2s1/2) of 15N as well as a neutron skin in the first excited state (2s1/2) of 15O. 相似文献
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Lin Meng Wenkai Xie Shenggang Liu 《International Journal of Infrared and Millimeter Waves》1999,20(8):1493-1499
The focusing properties of high energy electron beam in ion channel is investigated in the paper. The collisions of electrons with the neutral gas and the ionization resulted are considered to study the formation of ion channels with PIC method. The effects of various parameters on the beam focusing are analyzed. 相似文献
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无规位相板在实现靶面均匀辐照方面的性能分析 总被引:3,自引:0,他引:3
数值分析的结果表明:尽管实际辐照靶面的激光光束其振幅和位相是涨落变化的,但是,使用无规位相板同样能改善光束辐照靶面的均匀化程度;无规位相板取不同的无规位相分布对靶面辐照均匀化的影响较小。还讨论了靶面离焦时其光强分布的变化情况。 相似文献