June 24, 2013
Sustainable Roadmap for Fusion Propulsion
Dr. Jason Cassibry from the University of Alabama in Huntsville shared the history of fusion propulsion as well as the University of Alabama in Huntsville’s research on fusion propulsion. Dr. Cassibry claims that pulsed fusion is more powerful with a lower launch cost than conventional solid and chemical rockets. Fusion can also reduce travel time in comparison to chemical and nuclear power. The feasibility of fusion propulsion was first mentioned by Clauser in 1958. A steady state z-pinch with a magnetic nozzle was researched.
Dr. Cassibry mentioned that some NASA missions were only enabled because of fusion. The main design trade-off was cost benefit for increasing reliability versus cost for repairs. From 1999 to 2003, NASA Marshall Space Flight Center worked on plasma driver magneto-inertial fusion. In 2000, NASA conducted a fusion propulsion workshop, where various propulsion concepts were evaluated. Such concepts included the colliding beam FRC and the magneto-kinetic expansion concept. Even with all the research in fusion, it is a very difficult process to perfect. Some of the most common problems for fusion are handling temperatures, reactor sizes, and rarity of key fuels (ex: tritium).
The research at the University of Alabama in Huntsville is concentrating on z-pinch technology. Z-pinch technology generates x-rays in hot plasmas. A large current is created across a plasma cylinder, where a self-induced magnetic flux occurs at very high temperatures. One goal is to turn z-pinch technology into a thruster for hypersonic nozzles.
The University of Alabama in Huntsville is also looking into modeling approaches for z-pinch fusion propulsion. One main technical challenge includes the small time scales of the reactions that occur. They are also looking into a generic pulsed thruster model. The continuum models coupled with Maxwell’s equation was also discussed in some depth.