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

• Published in: Annales Geophysicae
• Main Authors: Kero, A., Bösinger, T., Pollari, P., Turunen, E., Rietveld, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Verlag 2000
• Subjects: article; Verlagsveröffentlichung; EISCAT
• Online Access: https://doi.org/10.1007/s00585-000-1210-8; https://noa.gwlb.de/receive/cop_mods_00036680; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00036634/angeo-18-1210-2000.pdf; https://angeo.copernicus.org/articles/18/1210/2000/angeo-18-1210-2000.pdf

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 Ne, Te and Ti 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)