Theory of High-Impedance Radio-Frequency-Force Plasma Devices

It is shown that in the absence of a magneto-static field, in the case of high frequency and high impedance, the steady force exerted by an rf field on a plasma is essentially proportional to the energy density gradient of the rf electric field. As an example, a simple rf plasma propulsion problem is solved, involving a plasma and an electrode structure, both of finite extent. The solution is consistent with experimental results which show that a finite body of plasma whose density is greater than critical is pulled in the direction of increasing electric field whereas a plasma whose density is less than critical is pushed in the direction of decreasing electric field.