CURRENT CONVECTIVE INSTABILITY IN THE DIFFUSE AURORA

A stable E × B gradient drift geometry can become destabilized by a current along the magnetic field. This type of instability is generically called the current convective instability. This instability may be responsible for the diffuse auroral scintillation causing F region irregularities observed by the DNA Wideband satellite. In these phenomena the northward TEC gradient dominates the altitude electron density gradient. We have investigated a simple plasma fluid model and found that instability results for −k · Vd > k · (cEo/Bo) (νi/Ωi) where Vd is the relative drift (precipitation current) between ions and electrons along Bo, Eo is the westward ambient electric field (⊥Bo), and νi and Ωi are the F region ion‐neutral collision frequency and ion gyrofrequency. This paper is not subject to U.S. copyright.