On the origin of anisotropic shielding of non-magnetic plasma column

Plasma is used as a shielding material in special applications where instantaneous tuneable shielding is required. Most of the analysis in the past treats non-magnetic plasma as a uniform medium with complex permittivity, which is not true due to the sustaining current that is needed to keep the plasma alive. The externally applied electric field causes anisotropic permittivity of plasma, and thus directional shielding effective as well. The origin of the anisotropic permittivity is the directional effective conductivity, which is the result of average drift velocity difference in the electric field direction. This document gives some scenarios to illustrate this point.