Antiproton annihilation dynamics for advanced space propulsion

Summary form only given, as follows. Summary form only given. One of the most promising propulsion systems that could be utilized in interplanetary travel is the gasdynamic mirror fusion rocket (GDM). In this work the use of antiprotons to initiate the fusion reactions in the GDM is examined as a potential replacement of the neutral beam injection system often cited in connection with fusion power reactors. The effectiveness of this approach depends critically, however, on the ability of the antiprotons to penetrate the plasma and reach the center of the engine without undergoing many annihilation reactions along the way. Using expressions for the annihilation rate per unit distance and the stopping power of antiprotons in a fully ionized hydrogenous plasma we calculate the annihilation distribution and the fraction of antiprotons that reach the central region in a relatively cold D-T plasma. We apply these results to a system with various plasma parameters and find that the annihilation rate is increased as the electron temperature is decreased. The amount of antiprotons needed to ignite the plasma is also calculated.