Equilibrium Potential Well due to Finite Larmor Radius Effects at the Tokamak Edge
Authors: W.W. Lee, R.B. White
Abstract: We present a novel mechanism for producing
the equilibrium potential well near the edge of a tokamak.
Briefly, because of the difference in gyroradii between electrons
and ions, an equilibrium electrostatic potential is generated in
the presence of spatial inhomogeneity of the background plasma,
which, in turn, produces a well associated with the radial
electric field, Er, as observed at the edge of many tokamak
experiments. We will show that this theoretically predicted Er
field, which can be regarded as producing a long radial wave
length zonal flow, agrees well with recent experimental
measurements. The relationship between the equilibrium
configuration used in the present study and that of the
Woltjer-Taylor state will be discussed.
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