A novel plasma state has been found [C. Akçay, J. Finn, R. Nebel and D. Barnes, Phys. Plasmas 24, 052503 (2017)] in the presence of a uniform applied axial magnetic field in periodic cylindrical geometry. This state is driven by external electrostatic fields provided by helical electrodes, and depends on radius r < r w and mθ − nζ, where m = n = 1, θ is the poloidal angle, and ζ = z/R is the toroidal angle. In this reference, the strongly driven form of the state was found to have a strong axial mean current density, with a mean-field line safety factor q 0 (r) just above the pitch of the electrodes m/n = 1 in the interior, where the plasma is nearly force-free. However, at the edge the current density has a component perpendicular to B. This perpendicular current density drives nearly Alfvénic helical plasma flows, an notable feature of these states. This state is being studied for its possible application to DC electrical transformers and possibly tailoring the current profile in tokamaks. We present results on several issues of importance for these applications: the transient leading to the steady state; the twist and writhe of the field lines and their relation with the current density; the properties of the current density streamlines and length of the current density lines connected to the electrodes; the sensitivity to changes in the velocity boundary conditions; the effect of varying the radial resistivity profile; and the effects of a concentrated electrode potential.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.