University of Illinois Space Propulsion

In a technical paper published last year, researchers from Universe of Illinois and from the Air Force Research Laboratory have described how a dense plasma focus device using hydrogen-boron fuel, (what we call “focus fusion”) can be used for space propulsion. The paper, authored by Robert Thomas, Yang Yang and George Miley of University of Illinois and Franklin Mead of Air Force Research Laboratory, calculated what the main characteristics of such a fusion rocket would be and described the main areas that still required research. Dr. Miley’s laboratory carried out a series of experiments with the plasma focus in collaboration with Focus Fusion Executive Director Eric Lerner in 1994, as well as other research with the device.

The Illinois-Air Force collaboration found that ion temperature had to exceed electron temperatures by a factor of 8-20 for good performance, while the simulation of the LPP design yield a temperature ratio that varied from 9 to 17. The new study actually came to slightly more optimistic conclusions, determining that fusion yield could exceed input energy by as much as three times, more than the doubling predicted by the LPP simulation.

Dr. Thomas and collaborators, like LPP and Focus Fusion Society, point to the prospect that high magnetic fields could reduce x-ray cooling of the plasma and conclude that electricity could be generated directly at high efficiency. They concluded that a “DPF rocket could be attractive for earth to orbit missions, as well as fast lunar/interplanetary missions.”

The paper was published in the proceeding of the Space Technology and Applications International Forum-2205, AIP Proceedings Series, p536.