Experimental measurements of Toroidal Alfvén Eigenmodes (TAEs) on JET with the AEAD system and simulations with the Gyrokinetic Toroidal Code (GTC).

The resonant detection and measurement of the damping rates of Alfvén Eigenmodes (AEs) is of critical importance to the design of experiments and development of models of AE stability [1]. We performed experimental measurements on JET with the AE Active Diagnostic (AEAD), and theoretical modelling using state of the art MHD and gyrokinetic codes.

The AEAD has undergone a major upgrade [2]. It can provide a state of the art excitation and real-time detection system thanks to its new amplifiers, filters, digital control system and to the newly installed magnetic probes. Weakly-damped AEs have been resonantly probed with external antennas. With GTC [3] we have simulated both stable and unstable AEs by using equilibria and diagnostic data from JET pulses dedicated to TAEs studies. Good agreement was obtained between simulations and experiments which adds confidence to further predictions for next-step burning plasma experiments, including JET and ITER.

[1] W.W.Heidbrink, Phys. Plasmas 15, 055501 (2008)

[2] P.Puglia et al., Nucl. Fusion 56, 112020 (2016)

[3] Z.Wang et al., Phys. Rev. Lett. 111, 145003 (2013)