Modelling of Flowing Plasma in the Magnetic Field of the Small Volume Plasma System Experiment

Abstract

A flow model for a magnetized plasma has been developed to investigate the flow dynamics in the small volume plasma system (SVPS) experiment. The SVPS experimental conditions require the model to describe a stationary, collisional, quasineutral, axisymmetric plasma. Also, the ions are cold while the electrons are isothermal and in thermal equilibrium, obeying the Boltzmann relation. In a plasma flowing along a magnetic field, the velocity of ions along the magnetic field lines is much greater than the velocity perpendicular to the field. The latter feature permits a unique ordering of the relevant variables, when the flow equations are transformed to the magnetic coordinate system (MCS), where the coordinate axes are parallel and perpendicular to the field lines. The ordering of the flow variables in the MCS allows a further simplification of the flow equations, by permitting their splitting into set of reduced, simplified equations. The SVPS experimental data are used to provide the requisite boundary conditions for initializing and solving the reduced flow equations on a magnetic coordinate grid along the different lines of the MCS. An important aspect of the present work is the validation of the splitting scheme used to derive the simplified and reduced flow equations. This is achieved by an in-depth comparison of the predictions from the model equations with the experimental data. The obtained numerical results compare favourably with the SVPS observations and have been discussed rigorously. The model developed here provides a framework for exploring magnetized plasma dynamics in the given cylindrically symmetric magnetic field configuration and can be further extended to more complex configurations.