Heating of heavy ions on auroral field lines in the presence of a large‐amplitude hydrogen cyclotron wave

Abstract

Heating of heavy ions is studied analytically and by means of numerical simulations in the presence of a large‐amplitude hydrogen cyclotron wave which is commonly observed on auroral field lines. Both one‐ and two‐dimensional numerical simulations showed a decay instability resulting in strong heating of both the oxygen ions and the hydrogen ions. In particular, detailed results of simulations in two dimensions where E × B drift plays an important role indicate a much stronger heating of the oxygen ions than that in the one‐dimensional simulation. A high‐energy tail of the oxygen ions is commonly observed in the perpendicular distribution.