Electron collisional effects on lower hybrid drift instabilities in the ionosphere

Electron collisional as well as ion collisional effects have a significant effect on the stability analysis of lower hybrid drift modes in the ionosphere. Electron collisions stabilize the modes and cause a density gradient threshold for the instability not previously calculated. This threshold results in restrictions on the interpretation of 155‐ and 415‐MHz backscatter results as being due to lower hybrid drift instabilities and suggests measurements to determine whether the instability can account for the backscatter.