Electromagnetic Particle Injector (EPI) as a Fast Time Response Disruption Mitigation Concept*

The Electromagnetic Particle Injector (EPI) has the potential for delivering the radiative payload composed of micro spheres of B, BN or Be, inside the q = 2 surface on a 3-4 ms time scale, much faster, and deeper, than what can be achieved using present methods. Experimental tests on a proto-type system have been able to verify the primary advantages of the EPI concept over other disruption mitigation concepts for a tokamak. These are the rapid response time and the capability to attain the projected speeds on this fast time scale. In preparation for a tokamak test of the concept, a much-improved compact system has been built. Compared to the initial test version, this system employs 2T magnetic field augmenting coils to substantially reduce the current through the system to attain the required velocity. Capability for radiative payload deposition in the core provides a means to suppress the formation of the runaway current. With EPI, one can precisely calculate the injection parameters needed for deep penetration into any plasma, including the ITER plasma, giving confidence that simulation capabilities validated with present tokamak experiments can be used to reliably project to ITER.