Notes:
This table gives one two peices of information. First, what sort of current you would need to draw in order to reverse the sheath potential in a dc sense, but also, Second, what fraction of a biasing period would be required (at most) for electrons to electrically neutralize the positive charge collected during the remainder of the rf period.
Note: In high density chlorine discharges, it has been seen that the negative ion density during the active glow is about equal to the electron density (at least as I remember it.) Therefore, Ni/Ne = 10 is an _over_ estimate of the negative ion density there for CW glows even though it is the lowest value that I use.
U(Bohm) >= SQRT[{e*T_e*(1+alpha_s)}/{M(1+alpha_s*gamma)}]
alpha_s = the ratio of the negative ion density to electron density at the sheath edge.
gamma = the the ratio of the electron to negative ion temperatures at the sheath edge.
|