Analytical description of a collisional plasma column in a vacuum arc centrifuge

Abstract

In this work the effects of electron-ion collisions in the plasma column of a vacuum arc centrifuge are modelled using a perturbation technique. It is found that the model agrees reasonably with an earlier fluid simulation, in which ion viscosity effects were also included. Using the perturbed solutions, the axial evolution of the steady-state separation profile is resolved, showing that the effect of electron-ion collisions is to improve separative performance with increasing axial position. The conditions under which separative performance are optimized are suggested. The non-uniformity in the axial magnetic field of a vacuum arc centrifuge caused by plasma rotation is also investigated. It is found that the non-uniformity is weak for standard operating conditions.

A flowing plasma model to describe drift waves in a cylindrical helicon discharge

“…In this paper, we employed a two-fluid model, which was developed originally for describing the wave oscillations observed in PCEN, 33,34,41 to study the low frequency oscillations in WOMBAT. To ensure that this model is consistent with WOMBAT, the measured and predicted plasma configurations were compared, including the equilibrium density profile and the space potential profile.…”

“…The steady-state velocities of ions and electrons can be written as v i = (0, ω i r, ν iz ) and v e = (0, ω e (r)r, ν ez (r)), respectively, where ω i is the ion rigid rotor rotation frequency, ν iz is the ion uniform axial streaming velocity, ω e (r) is the electron rotation frequency, and ν ez (r) is the electron streaming velocity. While treated in other work 41 , radial diffusion of both ions and electrons due to electron-ion collision is negligible. Here, length and time are normalised to R and 1/ω ic respectively, where ω ic = ZeB z /m i is the ion cyclotron frequency.…”

“…In this paper, a two-fluid model, which was developed originally for the vacuum arc centrifuge by Hole et al 33,34 to explain oscillations observed in the density and electric potential, is applied to study low frequency oscillations observed in WOMBAT. We show that the equilibrium and perturbed density profiles and the space potential profile from the model and data are consistent.…”

Breakdown of the Brillouin limit and classical fluxes in rotating collisional plasmas

“…[16][17][18][19] Besides these classical fields, the general problem of angular momentum conversion [20][21][22] between static magnetic field, wave helicity, and plasma vorticity has received considerable attention in other contexts such as (i) particle acceleration and magnetic field generation in plasma channel and plasma bubble, [23][24][25] (ii) resonant particle acceleration and isotope separation with magnetized cylindrical particles beams, 26,27 (iii) mass separation with rotating crossed fields configurations, [28][29][30] (iv) and plasma propulsion. 31,32 Within the framework of most of these various studies, the problem of angular momentum dynamics in cylindrical magnetized plasmas has been mainly considered in the collisionless regime where rigid body rotations provide a simple and universal model; [9][10][11][12] although, in the collisional regime, resistive magnetohydrodynamic and perturbative models have been used to address the issue of collisional dissipation, 33,34 the collisional extension of the universality of rigid body rotations has never been explored. Rigid body rotation has been predicted and observed in collisionless plasmas experiments dedicated to isotope separation in vacuumarc 35,36 and nonneutral plasmas studies.…”

Plasma Mass Filters For Nuclear Waste Reprocessing

“…Because of the collisions, the plasma will probably behave like a rigidly rotating body, with no sheared rotation [28]. Sheared rotation is the most common way of stabilizing a rotating plasma [29,30].…”