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utilized as the primary energy transfer mechanism in a nuclear reactor, it is expected that radiant energy transfer will also produce some of the most difficult but interesting theoretical and engineering problems associated with plasma core concept.

        The usual impetus for studying a new reactor concept is derived from the continuing efforts of the nuclear industry to develop more efficient and economical reactors (1,2,3). The plasma core reactor is an exception. The initial interest in the gaseous or plasma reactor concept (4-11) has resulted in research directed toward its use as a high performance space propulsion device. In order to compare the propulsion potential of the plasma core reactor with other concepts, the specific impulse,* I s, is used as a relative measure of performance. Since specific impulse is related to propellant mass (M) and temperature (T) through the relation Isp  /T79 (12), a high temperature, low molecular weight propellant is desirable. The maximum propellant temperature is limited by the maximum allowable temperature of the reactor fuel. The temperature limit in a solid core reactor is the fuel melting point, while the temperature of a liquid core


        *Specific impulse is defined as engine thrust per unit weight flow rate of propellant.