The observation of the ion composition in transition layer with the rocket-borne impedance probe

The impedance probe has been used for the measurement of electron density in plasma. The equivalent capacitance of the ion sheath formed around the probe can be estimated from the gyrofrequency. The information on ions can be provided from the sheath capacitance. The sheath structure depends on ion composition. The ion composition changes from NO+ and O2+ to O+ at about 160 km altitude, which is the transition region. The measurement of the altitude of the transition layer is discussed on the basis of the sheath capacitance. (Yoshimori, M.)