Cathodic-arc plasma density, radial profile, and total plasma inventory as measured by microwave interferometer and Faraday cup

The total amount of plasma, peak plasma density, and plasma density radial profile are derived from a series of measurements of ion current density (with a Faraday cup) and integrated electron line density (with a microwave interferometer) for a cathodic arc derived plasma. Comparisons are made between cathode material (erbium and titanium), arc current, background gas pressure, and the presence or absence of a series magnetic solenoid around the coaxial anode and cathode.