Generation of auroral arc elements in an inverted‐V arc due to ion cyclotron turbulence

Abstract

By using a two‐dimensional particle simulation it is shown that the electrostatic ion cyclotron turbulence driven by the field‐aligned current on auroral field lines can lead to striations of the current into east–west aligned current sheets of ion gyroradius scale (La ∼ ρi). Physical mechanism for the striation can be identified with nonlinear mode couplings of ion cyclotron waves resulting in condensation of the wave energy into a zero‐frequency mode. It is proposed that the auroral arc elements (La ∼ ρi), which collectively give rise to the inverted‐V arc (Lυ ≫ ρi), can be produced by the east–west aligned striations of the field‐aligned current on inverted‐V field lines.