Dynamic RF Power Control for DIII-D ICH/FAST Wave Operation
Authors: C.C. Kung, et. al.
Abstract:
Thanks to the broadcast industry, high
power transmitters between 10 MHz and 100 MHz in
megawatts power range can be obtained at a reasonable
price. Thus, we could take advantage of such
development to use this frequency range for ion
cyclotron and harmonics fast wave heating in the
magnetic fusion energy research.
Usually, antenna loading conditions can be fine
tuned to meet the fusion plasma heating needs.
However, the edge localized mode (ELM) during the
plasma operation can cause up to 90% of RF power
reflections when it appears at the antenna straps. In
order to protect the transmitters, the whole transmitter
system would shut down completely via crowbar under
these conditions. This forceful shutdown can lead to
unwanted wear and tear on the high voltage DC power
supply system and impact the plasma operation due to
the RF power interruption.
In order to enable the transmitter to "ride" through
the ELM induced high power reflections and avoid
unwanted crowbar conditions, we can modify the
transmitter power control and protective circuitry to
accommodate the ELM"s perturbations.
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Submitted to: SOFE 2013 Proeedings (June 0213) 25th Symposium on Fusion Engineering, San Francisdco, CA (June 10-14, 2013)
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Download PPPL-4890 (pdf 582 KB 8 pp)
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