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Title: 110 GHz ECH heating system for DIII-D

Conference ·
OSTI ID:5182816

Electron cyclotron heating (ECH) has been demonstrated to be effective at heating tokamak plasmas in DIII-D and other tokamaks. Extension of these results to high frequency and higher power in DIII-D is planned using 110 GHz outside launch X-mode at the second harmonic. A 2 MW system constructed from four modules, each using a Varian 0.5 MW 110 GHz gyrotron, is scheduled to be completed by May 1992; construction of a complete 0.5 MW module is complete and is in checkout. The results of the engineering test will be reported. A unique feature of this design is the use of strongly guided HE{sub 11} modes to transmit the power over the long distances required. The choice of a strongly guided HE{sub 11} mode for transmitting the ECH power was influenced by the compact waveguide, the non-critical alignment which allows waveguide flex, the ability to use mode selective directional couplers, and finally, continuous curvature bends can be used since there are no trapped modes. The waveguide is evacuated to handle the required power density. Implementation of this design required the development of mode converters to convert from the TE{sub 15,2} mode generated by the gyrotron to the desired HE{sub 11}. Results of the high power tests of the mode converters and transmission components will be presented. 2 refs., 1 fig.

Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC03-89ER51114
OSTI ID:
5182816
Report Number(s):
GA-A-20627; CONF-910869-6; ON: DE91018732; TRN: 91-026461
Resource Relation:
Conference: 9. topical conference on radio frequency power in plasmas, Charleston, SC (United States), 12-14 Aug 1991
Country of Publication:
United States
Language:
English