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 v(d) with respect to the ions, and the electric field E for many bias-voltage combinations are used to demonstrate the controllability of the ratio upsilon(E)/upsilon(d), where v(E)=ExB/B-2, 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.