Joule Heating and the Atmospheric Dynamo by Stephan Buchert, IRF Joule heating occurs when electric fields transformed into the local reference frame of the neutral gas are non-zero. This is also the condition for having finite electric currents according to the well-known Ohm's law for the ionosphere. A prominent cause of such electric fields at high latitudes is magnetosphere-ionosphere coupling. However, also the atmospheric dynamo is known to drive currents, and it is dominating at mid-latitudes. An atmospheric dynamo should also occur with gravity (buoyancy) waves in the dynamo region. Based on a paper by Parker (1996) we present the dynamic equations describing the coupling between neutrals and ionospheric plasma. E3D will be an important tool to study this coupling at small to intermediate scales. However, additional independent measurements, e.g. in-situ with rockets and satellites, will be needed as well.