Electron temperature dependence of PMSE power: experimental and modelling results Original Research Article

Joint PMSE - ionospheric heating experiments using the EISCAT VHF radar and the Heating facility were conducted at the EISCAT site near Tromsø during the period July 9–14, 1999. Height profiles of backscattered power for four different combinations of heating parameters and ionospheric conditions are presented and analysed with the help of an ionospheric heating model. The decrease of PMSE power during heating has a height dependence and varies from one case to another. This variability of the heating effect on PMSE power may be related to height-dependence and case-to-case variation of the electron temperature enhancements due to the ionospheric heating as well as to differing undisturbed levels of PMSE power. The possible relation of electron recombination, diffusion, and aerosol charging to the observed reduction of PMSE power during heating is discussed. An increase of electron diffusivity due to the temperature enhancement seems to be the most likely factor affecting PMSE during the experiments.