Generation and Diagnosis of Synthesized Plasma Streams

A contact-ionization source is described which generates a cesium ion stream characterized by a high degree of order in the ion motion. Electrons are added to form a quiescent, collisionless plasma stream. Diagnostic instruments are described for demonstrating the properties of the plasma streams. Ion densities range from 5×107 to 1×1011 ions/cm3 in the source region, at accelerating voltages from 100 V to a few thousand volts, depending on the experimental application. Conical expansion of the beam reduces the densities in downstream regions. Electron temperatures in the beams range downward from the ∼2500°K emissive wire temperature. Means are described for increasing electron temperatures to several times this value, with resultant increase in beam divergence.