Electron Temperature Probe on Board Japan's 9th Scientific Satellite “OHZORA”

Overview of the electron temperature measurement which was carried out by means of the satellite “OHZORA” is presented. The principle of the measurement, the measuring circuit and several preliminary data are described. One of the findings which were obtained from one year observation is the unisotropy of the electron temperature. The electron temperatures show the difference when the sensor electrodes take the parallel and perpendicular directions with respect to the geomagnetic line of force; T_// is 1.2∼1.7 times higher than T_⊥. This tendency is found all through the day in the auroral region but is limited to the daytime in the equatorial region.