Insitu measurements of Te in the lower ionosphere — A review Review Article

The most basic long time problem of the insitu electron temperature measurements in the ionospheric E region is “why Te is very often higher than possible Tn at the height of ∼100 km. Apart from this fundamental problem, there are at least three research subjects on the behavior of electron temperature which have not been clear so far. These are: (1) electron temperature in the Es layer, (2) electron temperature in the equatorial electrojet, (3) electron temperature near Sq focus. Essential requirement for the reliable measurement is to avoid the effects due to electrode contamination, which can be done by using a glass tube-sealed cylindrical electrode. After the counter moves against the electrode contamination is processed, the sweep rate of the probe bias should be taken into account; the sweep rate should be fast enough to measure electron temperature in rapidly changing region such as in Es and to remove the spin effect of the rocket. Several other factors which might influence the accurate measurements are also discussed.