98
Advanced
Design of Quasi-Optical Launchers for Fusion Plasma Heating--Calabazas Creek Research, 20937 Comer Drive,
Saratoga, CA 95070-3753;
408-741-8680
Dr.
Jeffrey Neilson, Principal Investigator, jeff@calcreek.com
Dr.
R. Lawrence Ives, Business Official, rlives@calcreek.com
DOE
Grant No. DE-FG03-00ER82965
Amount:
$375,000
Current
high power gyrotron tubes, used for heating fusion plasmas, produce power in
high order TE modes, which are converted to a Gaussian like mode through use of
an internal mode converter and launcher. However,
these converter systems typically achieve only 85-90% efficiency for conversion
of cavity output power to a usable Gaussian mode, leading to significant
efficiency degradation. Current
analysis software used to design the mode converter and launcher system are
based on approximations that limit
solution accuracy, thereby limiting the ability to achieve designs with high
efficiency. This project will
develop an exact integral formulation of the problem that will allow for the
design of high efficiency converter/launchers. In Phase I, an exact magnetic field integral equation
analysis computer code, which used the forward-backward method for an iterative
solution, was developed. Using this
code, calculations for a test launcher had excellent agreement with
measurements, demonstrating the feasibility and accuracy of the integral
equation approach. In Phase II, an
advanced engineering code for the converter/launcher analysis will be developed
that uses integral formulation analysis and techniques to minimize the
computational load. A
high-efficiency mode converter and launcher system for use in a high average
power DOE gyrotron will be designed.
Commercial Applications and Other Benefits as described by the awardee: Successful development should increase the efficiency of Gaussian mode gyrotrons used for plasma heating in fusion devices. The technique should also be applicable to other overmoded, high-power microwave components such as waveguide converters, power combiners, elbows, and mirrors. These components have applications in research and medical accelerators, materials processing, and high-power millimeter wave radars.