Modulation of polar mesospheric summer echoes (PMSEs) with high-frequency heating during low solar illumination

Abstract. Polar mesospheric summer echo (PMSE) formation is linked to charged dust/ice particles in the mesosphere. We investigate modulation of PMSEs with radio waves based on measurements EISCAT VHF radar and heating facility during low solar illumination. The were made August 2018 2020 around 20:02 UT. Heating was operated cycles intervals 48 s 168 off. More than half observed show a PMSE decrease when heater an increase it switched off again. often increases beyond its initial strength. Less modulations have such overshoot. overshoots are small or nonexistent at strong PMSE, they not ionosphere influenced by particle precipitation. observe instances very large weak PMSE. varies strongly from one cycle next, being highly variable spatial scales smaller kilometer timescales shorter assumed for variation dust parameters. Average curves over several similar overshoot predicted theory previously. Some individual stronger reported previous studies, exceed values theory. A possible explanation that dust-charging conditions different either because reduced illumination midnight long-term changes ice conclude reliably derive parameters modulations.