First EISCAT measurement of electron-gas temperature in the artificially heated D-region ionosphere

A. Kero (1) , T. Bösinger (1) , P. Pollari (1) , E. Turunen (2) , M. Rietveld (3)

1 University of Oulu
2 Geophysical Observatory
3 EISCAT Scientific Association [Norway]

The ionospheric electron gas can be heated artificially by a powerful radio wave. According to our modeling, the maximum effect of this heating occurs in the D-region where the electron temperature can increase by a factor of ten. Ionospheric plasma parameters such as N_e, T_e and T_i are measured by EISCAT incoherent scatter radar on a routine basis. However, in the D-region the incoherent scatter echo is very weak because of the low electron density. Moreover, the incoherent scatter spectrum from the D-region is of Lorentzian shape which gives less information than the spectrum from the E- and F-regions. These make EISCAT measurements in the D-region difficult. A combined EISCAT VHF-radar and heating experiment was carried out in November 1998 with the aim to measure the electron temperature increase due to heating. In the experiment the heater was switched on/off at 5 minute intervals and the integration time of the radar was chosen synchronously with the heating cycle. A systematic difference in the measured autocorrelation functions was found between heated and unheated periods.

Key words: Ionosphere (active experiments; plasma temperature and density; wave propagation)

Domaines: Océan, Atmosphère; Sciences de la Terre

A. Kero, T. Bösinger, P. Pollari, E. Turunen, M. Rietveld. First EISCAT measurement of electron-gas temperature in the artificially heated D-region ionosphere. Annales Geophysicae, 2000, 18 (9), pp.1210-1215. ⟨hal-00316792⟩