LPP’s research team observed a recurrence of arcing problems within FF-1’s cathode and between the cathode and the steel plate it is attached to. Arcing occurs when the contact between two metal pieces is insufficiently close and current jumps through the gap, creating a spark. In this situation, electrons accelerate to the point that they can vaporize copper or steel. This vapor can then enter the plasma unevenly, creating asymmetries that interfere with the even compression of the plasma and thus reduce fusion yield. The team observed that arcing was occurring between the copper cathode rods and the copper cathode plate they are screwed into and, more extensively, between the copper plate and the steel buss plate from which it receives current.
After testing and eliminating various causes for the arcing, we concluded that the main problem was insufficient pressure applied to the electrical contacts. For the copper plate, we have added 16 more brass bolts to double the pressure, and smoothed the contact surfaces, while for the copper rods, we have added thin copper washers where needed to make a tighter fit.
Unfortunately, our test of the new fixes was delayed when an error in the assembly of the electrodes led to the breaking of the ceramic insulator that separates the cathode and anode. We do expect to accomplish the test in the first half of February, and expect higher fusion yields to result.
Above: Double the bolts, double the electrical contact pressure!
