A HIGH-DENSITY PULSED ION-TRAP

By exploiting the synergy of two discharges in low pressure gases or g aseous mixtures, a pulsed electron beam with exceptional radial stabil ity has been obtained having a diameter less than 50 mu m over 40 mm. It acts as a pulsed high density ion trap for the ions created by elec tron impact along the beam. From the measured electron beam characteri stics and using a simple model, an ionic density of about 10(16) cm(-3 ) and a depth of the potential well of the order of a few keV has been inferred. The parameters of the trap can be tuned to assure a full io nization of the gas inside the tube current with a significant probabi lity for multiple ionization, the recombination rate being reduced due to the mismatch between the electron and ion velocities. Preliminary results on Ar III and Ar IV emission lines from the plasma channel ass ociated with the beam are reported.