Magnetic Field Scaling of Asymmetry-InducedDiffusion in a Non-Neutral Plasma


Joshua Williams

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The dependence of radial particle flux on the confining magnetic field is a key piece of information for understanding the mechanism of asymmetry-induced transport in pure electron plasmas. Resonant particle transport theory predicts that is proportional to the density gradient, a mobility term, and a Gaussian term. The latter two terms are functions of the variable x, which is proportional to, where is the plasma rotation frequency, is the frequency of the applied asymmetry, and l is its azimuthal mode number. Contributions from the magnetic field arise in multiple terms of the flux equation, thus complicating its dependence. The B-field explicitly appears as a scaling constant, but since the mobility and Gaussian terms are both functions of , the B-field also enters those terms in the form of the plasma rotation frequency. To work with the B-field scaling exclusively, the mobility and Gaussian terms must be eliminated. Working with applied frequencies that satisfy the condition produces this desired cancellation. We have acquired vs. r data for a range of asymmetry frequencies at particular center wire potentials for the case. Those points that met the specified condition were used to construct plots of vs. Using log-log plots of the slopes of these graphs versus magnetic field, we have found that the diffusion coefficient D of the flux is proportional to. This is in contrast to that of current resonant particle transport theory which predicts a scaling for the plateau regime.


Dennis Eggleston




Ford Research Endowment

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