We extend the previous analysis of the current convective instability as applied to the diffuse auroral situation (Ossakow and Chaturvedi, 1979) to include ion inertial effects, important at high altitudes; and to the case in which ions are highly collisional (nonmagnetized), a situation that is realized at E region altitudes. In the inertial domain the instability growth rates are comparable to those found in the collision dominated domain. This extends the applicability of the instability process to high altitudes. The relavance of the instability to the E region is discussed. Finally, electromagnetic effects, which can be important for long wavelengths, are considered and are found to be small in ionospheric situations.