Characteristics of an electron beam excited plasma

Summary form only given. We report the results of optical measurements on a plasma which is produced by propagating an electron beam through a low pressure gas. The electron beam energy and current can be varied up to 50 keV and 10 mA. The background gas pressure is varied up to the 1 Torr range, of helium and argon. Optical spectroscopy and interferometry techniques are used to characterize the spatial, density and temperature profiles of the plasma. These basic studies relate to a new method of modifying the ionization threshold and ionization rate of plasmas produced by high powered lasers. The electron beam provides free electrons, and a preionized plasma, which affect the laser ionization process. The laser produced plasma will be used later in experiments related to plasma wave accelerators.