Diagnostics of a Diluted Ultracold Plasma Using the Autoionization Effect of Rydberg States of 40Ca Atoms

A sensitive method to study a dilute ultracold plasma based on the autoionization resonances of Rydberg atoms is demonstrated. Ultracold 40Ca Rydberg atoms are prepared in a continuously operating magneto-optical trap. A method that allows the detection of the plasma with ion and electron densities below 109 m–3 is shown. Experimental studies of resonances at the two-photon null null null null null null null null null null null null null null...