Instability in lower ionosphere at low latitude

In the lower ionosphere, a dc electric field is induced by the collision between charged and neutral particles. In addition, there is a vertical electron density gradient due to the presence of the Hall current induced by the Earth magnetic field and the partially ionized plasma in the ionosphere. Under these conditions, their combined effects will cause instabilities in this region. Based on the two-fluid plasma equation, the growth rate of these instabilities is derived. Numerical simulation of this instability shows some fluctuation in electron density in the lower ionosphere 150 seconds after the disturbance. The spatial scale of the undulation is of the order of several hundred meters to several kilometers. In addition, it has a tendency to move in the vertical and horizontal directions. Furthermore, the observation made during the solar eclipse in Yunnan of 16 February 1980 is also discussed.