标题： 杂质在湍流磁化等离子体中的混沌输运的减少 显示英文标题

标题： Reduction of the chaotic transport of impurities in turbulent magnetized plasmas

摘要： 带电粒子在湍流静电势中的混沌输运设定了托卡马克等装置中等离子体约束的严重限制条件。 在本章中，我们考虑由ExB速度驱动的杂质运动，其中强磁场B(允许使用引导中心近似)是均匀且恒定的，而湍流电场则来自模型或数值流体代码。 哈密顿动力学决定了这些杂质的输运特性。 因此，一种能够减少哈密顿系统中混沌扩散的技术能够在某些近似下解决杂质径向输运的问题。 其总体思路是通过对哈密顿量进行微小而恰当的修改，在相空间中构建屏障。 我们通过数值模拟表明，这样的扰动能够显著减少示踪粒子的扩散，并讨论了这种额外修改的鲁棒性。 显示英文摘要

摘要： The chaotic transport of charged particles in a turbulent electrostatic potential sets the conditions of a severe limitation to the plasma confinement in devices such as tokamaks. In this chapter, we consider the motion of impurities driven by the ExB velocity where a strong magnetic field B (which allows for the guiding center approximation) is uniform and constant, and a turbulent electric field is obtained from models or from numerical fluid codes. Hamiltonian dynamics rule the transport properties of these impurities. Therefore a technique to reduce chaotic diffusion in Hamiltonian systems is able to address the issue of reducing the radial transport of impurities under some approximations. The general idea is to build barriers in phase space by a small and apt modification of the Hamiltonian. We show numerically that such perturbations are able to drastically reduce the diffusion of test-particles, and we discuss the robustness of such additional modifications.