Exploratory Test of Utility of Magnetic Insulation for Electrostatic Accelerators
Authors: L.R. Grisham, A. von Halle, A.F. Carpe, Guy Rossi, K.R. Gilton, E.D. Mcbride, E.P. Gilson, A. Stepanov, T.N. Stevenson
Abstract:
A recent paper [L. R. Grisham, Physics of Plasmas 16 043111 (2009).] proposed
that a magnetic field which enveloped each of the electrodes in an electrostatic
accelerator, along with their support structures, might suppress field emission of
electrons, and thus allow a higher electric field gradient to be applied between accelerator
stages without the onset of vacuum electrical breakdown. Such a magnetic field
configuration might be produced by flowing a substantial electric current through each
accelerator grid and its supports from high current low voltage supplies floated at each
accelerator grid potential. This experimental note reports a preliminary exploratory test
of whether this magnetic insulation approach might be of benefit at a modest magnetic
field strength which could be suitable for practical accelerator applications. This
experiment did not find evidence for an increase of the electrostatic potential gradient
which could be sustained across a vacuum gap when the cathodic (electron-emitting)
electrode was enveloped in a magnetic field of about 240 gauss. This note discusses a
number of possible explanations for this observation, as well as the inherent limitations of
the experiment.
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Accepted to: Physics of Plasmas (December 2011)
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Download PPPL-4721 (pdf 494 KB 11 pp)
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