Er...so can you prove to me that an electric current, conducted through a plasma, is indeed carried less than 99.9% by the electrons present?
Neutron flow huh, how's that conduct? Don't make excuses, like how unconfined, n --> p + e- (t(1/2) ~ 10 minutes) which could then conduct (i.e., very hot hydrogen plasma).
Yes, that too. A negative charge is also an excess of negative charge, and a positive charge is also an excess of positive charge.
Plasma physics perhaps not, but the principles are all there. Charge, ions, electric fields, matter; etc.
You can straightforwardly calculate that a singly (or more) ionized nucleus will move however many thousand times slower than an electron; thus, for some electric potential applied, more than two thousand negative charges (electrons) will be absorbed by the anode, and likewise emitted by the cathode, while the ions just kind of laze around and get knocked around by the nimble electrons.
Since all matter is composed of positive and negative charges mutually neutralized (roughly speaking), and electrons are the easiest particle to exchange one way or the other, it is definetly the most expedient to speak of a given electric potential as an excess or absence of electrons.
That's a hard sell, without a rope to compensate for reaction (presumably the energy is transferred by 1. kinetic energy and 2. decay energy) and half-life factors at long distances (at non-relativistic speeds). Also needs a nuclear reactor to produce, in lieu of anything better (I'm not aware of any neutron accelerators in existence). But I digress.