Scenario for a-driven Alfvén Modes in Deuterium-Tritium JET Plasmas
Alfvén Eigenmodes (AEs) driven by fusion-born a-particles are one of the most important ITER relevant issues. Continued investigation of AEs are motivated by the potential of such waves to redistribute a-particles in the core of the machine affecting the plasma heating profile, the magnitude of a-particle losses and the distribution of the helium ash. Furthermore, AE studies are also important due to their potential of providing valuable information on a-particles (slowing-down time and radial profile) and on plasma characteristics (q-profile evolution and D:T concentration). A possible future Deuterium-Tritium (DT) campaign on JET would present an opportunity to experimental study of a-particle driven AEs. However, a-particle driven AEs were not seen in JET DT Hmode discharges with record-high fusion yield and ba(0) @ 0.7%, and a-particle driven AEs could not be identified in JET discharges with Internal Transport Barriers (ITBs) because of the AE driven by ICRH. For exciting AEs with a-particles on JET, a dedicated scenario has to be developed. This presentation investigates the possibility of such scenario.