Steering tokamak plasmas is commonly viewed as a way to avoid disruptions and runaway electrons. Plasma steering sounds as safe as driving to work but will be shown to more closely resemble driving at high speed through a dense fog on an icy road. The long time required to terminate an ITER discharge compared to time over which dangers can be foreseen is analogous to driving in a dense fog. The difficulty of regaining plasma control if it is lost resembles driving on an icy road. Disruptions and runaways are associated with three issues—a solution to one tends to complicate the solution to the other two: loss of plasma position control, excessive heat deposition, and wall melting due to runaway electrons. All three risks must be addressed for ITER to achieve its mission and essentially eliminated before tokamak power plants can be deployed.

转向托卡马克等离子体通常被视为避免电子中断和失控的一种方式。等离子转向听起来与开车上班一样安全，但将被证明更接近于在结冰的道路上通过浓雾高速驾驶。与可以预见危险的时间相比，终止 ITER 放电所需的时间很长，这类似于在浓雾中驾驶。如果失去等离子控制，重新获得它的难度类似于在结冰的道路上行驶。中断和失控与三个问题相关——一个问题的解决方案往往会使其他两个问题的解决方案复杂化：等离子体位置控制的丧失、过度的热沉积和由于失控的电子导致的壁熔化。ITER 必须解决所有三个风险才能实现其使命，并在部署托卡马克发电厂之前基本消除所有风险。