Trail-A Tokamak RAIL Gun Limiter

An attractive new limiter concept is investigated. The Tokamak RAIl Gun Limiter (TRAIL) system directs a stream of moderate velocity pellets (100 to 200 m/s) through the plasma edge region to absorb energy and define the plasma boundary. The pellets are recycled, after cooling, to the injector in an electromagnetic mass accelerator. Heat fluxes of about30000 W/cm2 can be readily accommodated by the pellets, with very low recirculating power requirements ( about0.1%) for the accelerator. The mass accelerator velocity requirements are well within the present state of the art (several kilometres per second). Accelerators injecting pellets at about1 km/s can be used to control local plasma temperature and current profiles and to act as energy absorbers to shut down the plasma without damage to the first wall if a plasma disruption occurs