ABSTRACT
One of the most versatile experimental set-ups for studying the dynamics of plasma media has been the Q-machine, a device for producing relatively low temperature alkali plasma, which can be studied by means of Langmuir probes. Historically, it was one of the first devices to produce steady state plasma with a modest noise level, and to celebrate this, it was given the name Q-machine, with Q being an abbreviation for quiet. It is of interest also to investigate the full three-dimensional evolution of disturbances in unmagnetized plasma as well. This experimental set-up also had the advantage of producing plasmas with a large electron/ion temperature ratio, which is interesting for investigations of low frequency ion acoustic waves, for instance, since the damping of these waves turns out to depend critically on the electron-ion temperature ratio.
