用蒙特卡罗方法计算托卡马克中高能α粒子的能量损失及分布

THE ENERGY LOSS AND DISTRIBUTION OF THE ESCAPED ALPHAS ON THE FIRST WALL IN A TOKAMAK REACTOR

本文采用蒙特卡罗方法计算了托卡马克工程试验堆中高能逃逸α粒子的能量损失及分布。发现慢化过程中由于碰撞扩散而引起的能量损失远比过去预料的大。对抛物分布的等离子体,慢化过程的能量损失占总能量损失的绝大部分。而逃逸α粒子仅打在壁的上半部分或下半部分(由磁场方向决定),在极向和纵向上分布不均匀。在纵向上损失能量峰值偏离纵向磁场最小处,偏移方向由电流方向决定。

In this paper .using Monte-Carlo methods ,we have calculated the loss and distribution of the energetic alphas on. the first wall for four groups of plasma parameter . We get conclusions as follows : The collisional diffusion energy loss in slowing - down process is much larger than the drift loss for a parabolic plasma; the energy loss caused by the ripple is proportional to the square root of the ripple; the point of the maximum of the loss energy along toroidal angle on the first wall deviates from the minimum point of the toroidal magnetic field due to the toroidal magnetic field and the direction of the deviation is decided by the direction of the toroidal current; whether the escaped alpha particles bomb at the upper part or the lower part of the first wall depends on the direction of the toroidal magnetic field.