A segmented disk electrode to produce and control parallel and transverse particle drifts in a cylindrical plasma

A segmented disk electrode is described that produces and controls both relative drift parallel to the magnetic field and localized flow perpendicular to the magnetic field in a Q machine plasma. Measurements of the electron drift velocity vd with respect to the ions, and the electric field E for many bias-voltage combinations are used to demonstrate the controllability of the ratio vE/vd, where vE=E×B/B2, in a narrow channel between the regions that magnetically map to the segments. Radial electric fields of magnitudes ranging from 0 to ±3 V/cm localized within a current channel with parallel electron drift velocities up to half the electron thermal velocity have been produced with the segmented disk electrode.