IOP PUBLISHING PLASMA PHYSICS AND CONTROLLED FUSION Plasma Phys. Control. Fusion 50 (2008) 035009 (10pp) doi:10.1088/0741-3335/50/3/035009 Reversed shear Alfvén eigenmode stabilization by localized electron cyclotron heating

Reversed shear Alfvén eigenmode (RSAE) activity in DIII-D is stabilized by electron cyclotron heating (ECH) applied near the minimum of the magnetic safety factor (qmin) in neutral beam heated discharges with reversed-magnetic shear. The degree of RSAE stabilization, fast ion density and the volume averaged neutron production (Sn) are highly dependent on ECH deposition location relative to qmin. While discharges with ECH stabilization of RSAEs have higher Sn 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. (Some figures in this article are in colour only in the electronic version) 1