Reversed shear Alfven eigenmode stabilization by localized electron cyclotron heating

Reversed shear Alfven eigenmode (RSAE) activity in DIII-D is stabilized by electron cyclotron heating (ECH) applied near the minimum of the magnetic safety factor ( q(min)) in neutral beam heated discharges with reversed-magnetic shear. The degree of RSAE stabilization, fast ion density and the volume averaged neutron production ( S-n) are highly dependent on ECH deposition location relative to q(min). While discharges with ECH stabilization of RSAEs have higher S-n and more peaked fast ion profiles than discharges with significant RSAE activity, neutron production remains strongly reduced ( up to 60% relative to TRANSP predictions assuming classical fast ion transport) even when RSAEs are stabilized.