Runaway Generation during Fast Shutdown of High Current Tokamaks
Abstract
We present modeling results which evaluate the formation of relativistic (runaway) electrons[1] during the rapid shutdown of large tokamaks carrying tens of mega-amperes of current. The plasma is modeled using the TSC code as an axisymmetric evolving equilibrium. Plasma current termination is initiated in one of two methods under investigation: (1) by the injection of multiple pellets of hydrogen doped with an impurity (eg. Krypton) or (2) by the introduction of a liquid jet of high density hydrogen, possibly doped with an impurity. The densification and intense radiation that follows the injection brings the plasma to a low temperature (below 100 ev), which causes the plasma current to rapidly decay. The formation of runaway electrons through both Dreicer evaporation and the avalanche process, and the development of vertical displacements and plasma halo currents are all included in the modeling. DE-AC02-76CH03073 [1] M. N. Rosenbluth, S.V.Putvinski Nuclear Fusion, Vol. 37, (1997) 1355
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1998
- Bibcode:
- 1998APS..DPP.Q7S23S