Numerical modeling of microwave superheaters for fusion

Microwave Superheating is a promising method of heating a flowing gas to temperatures greatly exceeding the temperatures of surrounding material walls. A potential application of this concept is the use of the synchrotron radiation emission from a hot, magnetically-confined thermonuclear plasma to superheat the working fluid in the inlet region of a magnetohydrodynamic (MHD) generator to temperatures above that practical from conventional thermal heat sources. The simplest embodiment of the idea would employ a gas seeded with a material low ionization potential (probably one of the alkali metals) flowing through a ceramic tube. The ceramic wall is resistant to high temperatures, and allows the penetration of the microwaves without attenuation and wall heating. The gas could be Mercury vapor in the full sized fusion-relevant superheater, and perhaps either Argon or Helium in a proof-of-principle experiment. There is currently interest in an experimental collaboration with the Japanese to demonstrate the feasibility of the concept. They have developed both one and two dimensional hydrodynamic codes to study microwave superheating