Experimental results and outlook of the 2 MW 170 GHz coaxial-cavity gyrotron towards long pulse operation

The development of the modular short-pulse pre-prototype as base for the 2 MW, 170 GHz, CW coaxial-cavity gyrotron for international fusion project ITER and beyond is in progress at Karlsruhe Institute of Technology (KIT). The current modular pre-prototype configuration allows the generation of > 2 MW RF output power in short-pulses with a reasonable electronic efficiency of approximately 30 % without depressed collector operation. Recently, experiments with a new glidcop resonator has been performed. In depressed operation the overall efficiency of the gyrotron has been increased to ~48 %. In addition, an advanced water cooling system for a long pulse 2 MW gyrotron was developed. In this paper the experimental results, the suppression of the beam-halo and future plans for the 2 MW gyrotron will be presented.

[1]  John Jelonnek,et al.  A design proposal for an optimized inverse Magnetron Injection Gun for the KIT 2 MW / 170 GHz modular coaxial cavity gyrotron , 2015, 2015 IEEE International Vacuum Electronics Conference (IVEC).

[2]  John Jelonnek,et al.  A gun design criterion to limit the effects of the electron beam halo in gyrotrons , 2013, 2013 Abstracts IEEE International Conference on Plasma Science (ICOPS).

[3]  Jianbo Jin,et al.  Novel Numerical Method for the Analysis and Synthesis of the Fields in Highly Oversized Waveguide Mode Converters , 2009, IEEE Transactions on Microwave Theory and Techniques.

[4]  J. Vomvoridis,et al.  The self-consistent 3D trajectory electrostatic code ARIADNE for gyrotron beam tunnel simulation , 2004, Infrared and Millimeter Waves, Conference Digest of the 2004 Joint 29th International Conference on 2004 and 12th International Conference on Terahertz Electronics, 2004..

[5]  John Jelonnek,et al.  Electron trapping mechanisms in magnetron injection guns , 2016 .

[6]  John Jelonnek,et al.  Experimental results and recent developments on the EU 2 MW 170 GHz coaxial cavity gyrotron for ITER , 2012 .

[7]  G. Gantenbein,et al.  2 MW, 170 GHz coaxial-cavity short-pulse gyrotron - Investigations on electron beam instabilities and parasitic oscillations , 2013, 2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz).

[8]  Stefan Illy,et al.  2.2-MW Record Power of the 170-GHz European Preprototype Coaxial-Cavity Gyrotron for ITER , 2010, IEEE Transactions on Plasma Science.