Coupling properties of the LHCD launchers in the WEST experiments.

The aim of WEST [1] [2] is to master long pulses (> 30s and up to 1000s) and submit ITER like tungsten divertor tiles to power fluxes of 10 MW/m². To reach these goals, the Tore Supra Lower Hybrid Current Drive system (LHCD) constituted by two launchers with an injection power capability of 7MW/1000s has been upgraded to meet WEST new environment (diverted plasma, new launchers positions). In particular, the LH1 Full Active Multi-junction launcher (FAM) has been toroidally reshaped to match the new magnetic configuration. The poloidal curvature of the plasma has also been optimized to guarantee good coupling properties of the waves. During the last experimental campaign (October-December 2018), we obtained 30s repetitive pulses with a LH power of 2.7 MW (more than 2 hours of plasma during the experimental campaign) and 43 discharges with a total LH power from 4-5.3 MW. This paper describes the results obtained in term of coupling for both launchers. Thanks to Infra-Red (IR) monitoring it also assesses the reshaping of LH1 in terms of thermal loads due to supra-thermal electrons on the launcher edges. During the upcoming experimental campaign, the IR coverage will further improve allowing assessing the LH2 Passive Active Multi-junction launcher (PAM) thermal loads. [ABSTRACT FROM AUTHOR]