On the Scale of Auroral Model Experiments

The possibilities to scale down the physical properties of gaseous discharges with altered linear dimensions are considered with special regard to model experiments on aurorae. It is shown that the drift orbits can be transformed correctly, although the spiralling motion around the magnetic field lines cannot. This spiralling motion constitutes a very small ripple on the drift orbits in nature but a greater ripple in the experiments. However, this ripple seems to be of minor importance, and reasons are given for the view that the recent auroral experiments represent nature in a satisfactory way.