Estudo da impedância de plasmas anisotrópicos por meio do Teorema de Poynting

Abstract

We know that matter in the plasma state becomes good conductors and respond strongly to electromagnetic fields. This response may be used to probe quantities related to plasma, and is defined in terms of a conductivity tensor. In this work we present a brief study about the conductivity tensor calculus for anisotropic plasmas using the notation of Einstein and the Levi-Civita symbol. Making use of this conductivity tensor particularized for cold plasma model, we seek to determine expressions for resistance, reactance and plasma impedance defined by the Poynting’s theorem. In a simple analysis of the expression impedance we show an alternative way for determining the plasma density and plasma frequency in terms of easily measurable experimental parameters such as radius, distance between electrodes, the potential difference and external resistance to plasma. The method presented here is invasive as well as in cases where the diagnosis frequency and plasma density are performed by Langmuir probe, however the mapping through the impedance is shown mathematically and experimentally simpler to implement, and whith the possibility of being applied to pulsed systems as Tokamak and Theta-Pinch.