Current convective instability in the diffuse aurora

A stable E x 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 -kxV/sub d/>kx (cE/sub o//B/sub o/) (..nu../sub i//..cap omega../sub i/) where V/sub d/ is the relative drift (precipitation current) between ions and electrons along B/sub o/, E/sub o/ is the westward ambient electric field (perpendicularB/sub o/), and ..nu../sub i/ and ..cap omega../sub i/ are the F region ion-neutral collision frequency and ion gyrofrequency.