# Dictionary:Conduction current

Electrical current resulting from the motion of free charges under the influence of an electric field. The density of conduction current **J** at a point in an isotropic medium is , where is the conductivity and **E** is the electric field. Conduction currents usually are more important than displacement currents in electromagnetic prospecting, depending on the frequency range. Since in general **J** and **E** are vectors, the conductivity is a symmetric tensor given in Cartesian coordinates by

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If one of the coordinates is in the direction of maximum conductivity and one in the direction of minimum conductivity, nondiagonal elements vanish. In isotropic materials .