Pulsed High Density Fusion Rocket

摘要

It is recognized that nuclear fusion is the only source that can provide the prodigiousrnpower, as well as the large and available quantities of fuel required for manned deep spacernmissions. The difficulty however for most nuclear fusion space propulsion vehicles is the largernmass associated with the confinement system. This is primarily due to the large reactor sizesrnrequired for fusion gain with low beta steady state reactors. At the other end of the spectrum, forrnmost pulsed devices, the mass of the fast energy delivery systems becomes the problem. For thernlow energy, pulsed high density (PHD) fusion rocket, both these mass problems are avoided,rnmaking it possible to develop a very low mass (～20 MT) fusion propulsion system. The PHDrnfusion rocket based on the Field Reversed Configuration (FRC) plasmoid would enable rapidrnmanned interplanetary travel. In particular it would provide the necessary specific power (α > 1)rnto make a 100 day round trip manned Mars mission feasible. For the rapid Mars mission therntotal ship mass needed in IMLEO is less than 70 MT. The large mass reduction compared to otherrnfusion propulsion systems is accomplished in three ways. By producing the fusion burn in a small,rn(cm scale), high-density, drifting plasmoid, the reactor mass is greatly reduced due to the muchrnmore favorable surface to volume ratio. By adding the fusion burn energy to the fusion plasmoidrnincrementally in the form of translational plasma energy, the driver mass is also greatly reduced.rnThe ability to translate and expand the FRC plasmoid after fusion burn provides for a mechanismrnto very efficiently produce the necessary electrical power for the driver. Finally, the FRC (andrnslush propellant) is ejected by the expansion chamber nozzle field by Lorentz force acting directlyrnon the FRC plasmoid diamagnetic currents. In this process virtually all remaining FRC thermalrnand magnetic energy is converted into thrust. A major advantage of small scale pulsed fusion isrnthat the development should not require significant time or cost. The technologies involved in allrnaspects of the concept have been developed, and a proof of concept experiment is now underwayrnat our laboratory.