ANSYS HFSS as a new numerical tool to study wave propagation inside anisotropic magnetized plasmas in the Ion Cylotron Range of Frequencies

The paper demonstrates the possibility to use ANSYS HFSS as a versatile simulating tool for antennas facing inhomogeneous anisotropic magnetized plasmas in the Ion Cyclotron Range of Frequencies (ICRF). The methodology used throughout the paper is first illustrated with a uniform plasma case. We then extend this method to 1D plasma density profiles where we perform a first benchmark against the ANTITER II code. The possibility to include more complex phenomena relevant to the ICRF field in future works like the lower hybrid resonance, the edge propagation of slow waves, sheaths and ponderomotive forces is also discussed. We finally present a 3D case for WEST and compare the radiation resistance calculated by the code to the experimental data. The main result of this paper - the implementation of a cold plasma medium in HFSS - is general and we hope it will also benefit to research fields besides controlled fusion.Comment: 15 pages, 14 figure

Characterizations and first plasma operation of the WEST load-resilient actively cooled ICRF launchers

The paper discusses the characterization of the three high power steady-state and load-resilient ICRF launchers of WEST before their installation in the tokamak. These launchers have been characterized and validated in low-power experiments (milliwatt range) as well as in experiments at the nominal RF voltages and currents in the TITAN vacuum chamber (~30 kV and 915 A peak). The successful commissioning of two of the launchers during the WEST C3 campaign at ~1 MW power level is illustrated. Manual and real-time controlled impedance-matching of the launchers are discussed, as well as the validation of their load-resilience. Furthermore, several redundant and complementary protection systems have been validated and are reviewed in the paper

Sawtooth pacing with on-axis ICRH modulation in JET-ILW

A novel technique for sawteeth control in tokamak plasmas using ion-cyclotron resonance heating (ICRH) has been developed in the JET-ILW tokamak. Unlike previous ICRH methods, that explored the destabilization of the internal kink mode when the radio-frequency (RF) wave absorption was placed near the q = 1 surface, the technique presented here consists of stabilizing the sawteeth as fast as possible by applying the ICRH power centrally and subsequently induce a sawtooth crash by switching it off at the appropriate instant. The validation of this method in JET-ILW L-mode discharges, including preliminary tests in H-mode plasmas, is presented