负径向电场对荷电粒子运动的影响及其数值模拟

从负径向电场产生的电漂移改变荷电粒子运动的极向运动速度着手,推导出在负径向电场存在时安全因子的表达式,分析了安全因子对荷电粒子漂移位移和运动轨迹的影响。建立了在负径向电场条件下,荷电粒子在梯度磁场和曲率磁场中运动数学模型。通过数值模拟,获得了通行粒子、香蕉粒子的漂移位移和运动轨迹所呈现出的新特点和规律:负径向电场改变了荷电粒子的最大漂移位移。当荷电粒子的极向运动速度增加时,最大漂移位移减小,反之增大;改变了荷电粒子的运动轨迹,通行粒子的轨亦可能变为香蕉粒子的轨迹,香蕉粒子的轨迹可能变为通行粒子的轨迹,当电场达到足够的强度时,均成为在极向上顺时针运动的通行粒子轨迹。

EAST通行高能粒子激发的非共振鱼骨模不稳定性模拟

用磁流体动理学混合模拟程序M3D-K研究反剪切安全因子剖面下的非共振鱼骨模不稳定性。非共振鱼骨模指的是q_(min)略大于1的反剪切安全因子剖面下高能粒子激发的鱼骨模。分析能量共振关系,得到不同抛射角高能粒子激发非共振鱼骨模的物理机制。为了确定非共振鱼骨模稳定的参数阈值和鱼骨模不稳定性的变化趋势,在抛射角0.6时扫描非共振鱼骨模的参数,如注入能量E、高能粒子比压P_(hot)/P_(total)等,分析非线性过程中高能粒子的慢化分布、模结构的演化和鱼骨模扫频。抛射角在0.6、0.7和1.0时非线性的慢化分布变平趋势和实验中高能粒子变化一致,抛射角在0.6时非线性模结构由非共振鱼骨模模结构向其他高频模模结构演化,非线性过程的鱼骨模出现向上扫频符合经典鱼骨模的扫频。

Particle swarm optimization for train schedule of Y-type train routing in urban rail transit

The train schedule usually includes train stop schedule,routing scheme and formation scheme.It is the basis of subway transportation.Combining the practical experience of transport organizations and the principle of the best match between transport capacity and passenger flow demand,taking the minimum value of passenger travel costs and corporation operating costs as the goal,considering the constraints of the maximum rail capacity,the minimum departure frequency and the maximum available electric multiple unit,an optimization model for city subway Y-type operation mode is constructed to determine the operation section of mainline as well as branch line and the train frequency of the Y-type operation mode.The particle swarm optimization(PSO)algorithm based on classification learning is used to solve the model,and the effectiveness of the model and algorithm is verified by a practical case.The results show that the length of branch line in Y-type operation affects the cost of waiting time of passengers significantly.