On Sq and L Current Systems in the Ionosphere

Abstract

Ionospheric dynamo current system representing geomagnetic lunar variation on disturbed days is calculated. A characteristic current system L ^p is formed at high latitudes owing to conductivity enhancement in the auroral belt, which also influences the L currents at mid and low latitudes: the foci of mid-low latitude current vortices shift 4° toward high latitude. IMF B _z and B _y effects on mid-low latitude Sq are studied. Rapid variation of magnetospheric convection electric field caused by B _z variation will penetrate into the inner magnetosphere and then map onto the ionosphere along geomagnetic field lines, producing a characteristic electric field and current system, which will move the Sq foci and produce a magnetic disturbance of a few nT on ground surface. IMF sector effect on mid-low latitude magnetic filed is examined by using data from Beijing and Gangzhou in China. 3–5 nT effect is recognized.