Measurement of toroidal Alfvén eigenmode-driven fast-ion flows using an imaging neutral particle analyzer at ASDEX Upgrade

Alfvén Eigenmodes-driven fast-ion flows have been measured for the first time at the ASDEX Upgrade tokamak using an imaging neutral particle analyzer. The flow is such that particles are expelled from the mode location, losing energy as they move outwards. This flow aligns well with the projection of the lines of constant magnetic moment and constant E′ ( E ′ = E − ω P ϕ / n , with E being the particle energy, ω , n the mode frequency and toroidal number and P _φ the toroidal canonical angular momentum). The observed redistributions are consistent with full-orbit simulations performed with the ASCOT5 code, using the mode structure predicted by the linear gyro-kinetic code LIGKA.