Anomalous electron transport induced by multiple beam ion driven global Alfven instabilities

We investigate theoretically the electron thermal transport induced by multiple Global Alfv\'en Eigenmodes (GAE) in a toroidal plasma recently reported in NSTX when strong $P_{NBI}=6MW$ NBI heating was applied. A strong GAE activity correlates with such transport. The stochastization of electron longitudinal motion in the presence of the multiple oscillations is responsible for the electron transport. Application of the guiding center code, ORBIT, shows that the required level of the electron heat conductivity, $\chi_{e}\ge 10m^{2}/sec$ can be achieved in simulations with $\sim 20$ intermittently unstable GAEs with the local density perturbation amplitudes on the order of $\delta n_{e}/n_{e}=10^{-3}$. Our simulations address the requirements for GAE structure, amplitudes and the number of modes to achieve the electron heat diffusivity inferred from experiments. Results from the comparisons of the theory and recent NSTX experiments will be presented. The above anomalous electron transport potentially can have significant implications for fusion devices.