A two-fluid model developed originally to describe wave oscillations in thevacuum arc centrifuge, a cylindrical, rapidly rotating, low temperature andconfined plasma column, is applied to interpret plasma oscillations in a RFgenerated linear magnetised plasma (WOMBAT), with similar density and fieldstrength. Compared to typical centrifuge plasmas, WOMBAT plasmas have slowernormalised rotation frequency, lower temperature and lower axial velocity.Despite these differences, the two-fluid model provides a consistentdescription of the WOMBAT plasma configuration and yields qualitative agreementbetween measured and predicted wave oscillation frequencies with axial fieldstrength. In addition, the radial profile of the density perturbation predictedby this model is consistent with the data. Parameter scans show that thedispersion curve is sensitive to the axial field strength and the electrontemperature, and the dependence of oscillation frequency with electrontemperature matches the experiment. These results consolidate earlier claimsthat the density and floating potential oscillations are a resistive driftmode, driven by the density gradient. To our knowledge, this is the firstdetailed physics model of flowing plasmas in the diffusion region away from theRF source. Possible extensions to the model, including temperaturenon-uniformity and magnetic field oscillations, are also discussed.
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