Authors: V. Vekselman
Abstract: The chemical inhomogeneity of nuclear waste
makes chemical separations difficult, while the correlation
between radioactivity and nuclear mass makes mass-based
separation, and in particular plasma-based separation, an
attractive alternative. Here, we examine a particular class of
plasma mass filters, namely filters in which (a) species of
different mass are collected along magnetic field lines at
opposite ends of an open-field-line plasma device, and (b)
gyro-drift effects are important to the separation process. Using
a simplified cylindrical model, we derive a set of dimensionless
parameters which provide minimum necessary conditions for
effective mass filter function in the presence of ion-ion
and ion-neutral collisions. Through simulations, we find that
these parameters accurately describe mass filter performance in
more general magnetic geometries. We then use these parameters to
inform on the design and upgrade of current experiments, as
well as deriving general scalings for the throughput of
production mass filters. Importantly, we find that ion
temperatures above 3 eV and magnetic fields above 104
Gauss are critical to ensure feasible mass filter function when
operating at ion densities of 1013 cm-3 .
Submitted to: Carbon
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Download PPPL-5346
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