Theoretical study of the influence of sawtooth oscillations on fast ion transport and neutron emission in NBI experiments on JET

Abstract

The effect of sawtooth crashes on fusion reactions and the concomitant neutron emission are investigated analytically and numerically. The sawtooth induced redistribution of the plasma is described by a generalization of the Kadomtsev sawtooth reconnection model. Simple expressions for the changes in local and global rates of reactions produced by fast ions are obtained, which predict quite different results for tokamaks with different relationships between the q=1 radius, the radial profile width of fast ions and the plasma radius. Special attention is paid to numerical simulations of the changes of neutron emission in JET NBI experiments. Experimental results and numerical calculations of the line integrated neutron flux to the JET neutron profile monitor, and of the change of global neutron emission, are compared in detail and found to be consistent