论文标题
粒子传输中的无剪切分叉用于反向剪切tokamaks
Shearless bifurcations in particle transport for reversed shear tokamaks
论文作者
论文摘要
Tokamaks中的一些内部运输障碍与等离子体平衡曲线的极值附近有关。考虑到电场具有固定的非单调径向轮廓和静电波动，考虑到正在经历EXB漂移运动的血浆颗粒的指导中心轨迹来研究这种效果。另外，平衡构型具有非单调安全系数。运动方程的数值整合产生了具有无剪切屏障的符号图。通过更改安全系数的参数，可以观察到这些无剪切曲线的外观和破裂。使用分叉理论中的概念来解释连续的无剪切曲线破裂和恢复。我们还提出了与创建多个无剪切曲线相关的分叉序列。讨论了具有多个无剪切曲线的场景的物理后果。
Some internal transport barriers in tokamaks have been related to the vicinity of extrema of the plasma equilibrium profiles. This effect is numerically investigated by considering the guiding-center trajectories of plasma particles undergoing ExB drift motion, considering that the electric field has a stationary nonmonotonic radial profile and an electrostatic fluctuation. In addition, the equilibrium configuration has a nonmonotonic safety factor profile. The numerical integration of the equations of motion yields a symplectic map with shearless barriers. By changing the parameters of the safety factor profile, the appearance, and breakup of these shearless curves are observed. The successive shearless curves breakup and recovering is explained using concepts from bifurcation theory. We also present bifurcation sequences associated to the creation of multiple shearless curves. Physical consequences of scenarios with multiple shearless curves are discussed.
