Reply To: Global Warming

[asymmetric_implosion]

I’ve heard stories of the history but the stories are centered on the Mather focus. Like any verbal retelling, it grows a little with each retelling. The condensed version is the Mather PF discovery was an accident when a gas valve stayed open filling the chamber with gas during a thruster experiment. The tech operating the machine noticed a funny current shape. The Fillipov was intentional as an attempt to built a better Z-pinch. Both designs quickly scaled from ~500 kA to 2 MA in the 1970’s. It is not 100% clear why very few machines were ever operated above 2 MA. I know there are some technical issues but I get the feeling it was a political thing. Z-pinches are at the 26 MA level now from the same humble beginnings with their own technical problems studied and overcome. The history I’ve heard suggests Mather had a substance problem and was largely discredited with the funding agencies. Without his support, it was difficult to sustain the research at LANL. Take the history with a grain of salt.

The technical difference between the Fillipov and the Mather is the anode geometry. Both devices use a coaxial (concentric cylinder) geometry. The Fillipov focus has an anode length shorter than the anode diameter. The Mather geometry has an anode radius larger than the anode length. A few machines operate in the hybrid mode where anode radius and length are similar. The Mather seems to show superior neutron output for a given current. I believe there are solid technical reasons for this to be true but I don’t think anyone has proved it.