First CW experiments with the EU ITER 1 MW, 170 GHz industrial prototype gyrotron

A Validation Roadmap of Multi-Physics Simulators of the Resonator of MW-Class CW Gyrotrons for Fusion Applications

“…Since doubts still remained after 2015 on a proper value of k e f f in the simulations of cavities equipped with RRs, its calibration was attempted indirectly by comparing the results computed using the whole multi-physics simulator of the resonator to experimental data coming from different test campaigns on the EU 1 MW 170 GHz ITER gyrotron prototype, the resonator of which was cooled using an RR matrix. A first test campaign was performed at the Karlsruhe Institute of Technology Premises [14,40,41]. The tests were carried out for pulse durations up to 180 s. The results computed by the MUCCA tool for different values of k e f f , namely, 2000 W/m•K, 2600 W/m•K and 3600 W/m•K, were compared in terms of the frequency shift, due to thermal expansion of the cavity, to the experimental results, in different operating conditions, resulting in the picture reported in Figure 6a.…”

“…This solution has been adopted so far for the tubes manufactured in Europe. Cavities cooled using RR are inserted in the 140 GHz, 1 MW gyrotrons currently installed at W7-X [12], in the dual frequency devices commissioned in the TCV at the EPFL (Lausanne Switzerland) [11,13], and in the EU 1 MW 170 GHz first industrial prototype gyrotron [14] targeting ITER specifications [15,16]. RR-cooled cavities are also under design for the upgraded 1.5 MW gyrotron for W7-X [17] and for the next version of the EU 1 MW 170 GHz gyrotron.…”

2018 Status on KIT Gyrotron Activities

“…Pulses with a duration of 180 s (limited by the max. possible pulse length of the high-voltage power supply at KIT) delivered an RF output power higher than 0.8 MW with 38 % efficiency (in depressed collector operation) [6]. The second phase of the experiments is currently ongoing at EPFL-SPC, Lausanne.…”

A New Efficient Mirror Cooling for the Transmission Line of Fusion Reactor ECH Systems Based on Triply Periodic Minimal Surfaces

“…plasma by means of 32-MW-class gyrotrons [7] operating at 170 GHz (as those foreseen for ITER [8], [9], [10], [11]), long quasi-optical transmission lines enclosed in pipes under vacuum [12], and front-steering antennae composed of identical modular units of two mirrors [13]. The gyrotrons are grouped in four clusters of eight sources each: the power of a cluster is transmitted by a quasi-optical evacuated multibeam transmission line [14] up to two launchers in the DTT equatorial and upper ports, where the beams are launched into the plasma by independently steerable mirror antennas.…”