Henning wrote: Rezwan reported at Preliminary Evidence of Angular Momentum Effect that a higher current through the angular momentum coil (AMC) disturbs the forming of the initial sheath.
The here discussed ring at the cathode’s base could resolve that issue, enabling the sheath to form more easily although being disturbed by an extra magnetic field.
Glad there’s a view port in that area. Maybe a UV camera could see the sheath forming up?. Another approach to smoothing the sheath formation may be to reduce the number of turns in the coil, and/or using smaller diameter coils. But since that would be a tear-down and reseal operation (ugghhhhhh!), followed by at least a week of new experiments, that would be one of the very last resorts.
I read an abstract last night that some groups design the vacuum chamber as the cathode. Doesn’t seem to be any distinction about where the cathode ends in that case. I’ve also read of at least one group reversing polarity, but that would introduce a host of high voltage hazards if the anode were also the vac chamber wall.