Effect of radio. wave heating on polar mesospheric clouds

Polar mesospheric clouds (PMC) are composed of dust grains (aerosols) of submicron size at attitudes within 80-90 km. The grains, formed presumably by iced particles nucleated around small meteor dust, acquire electric charges and may change significantly the properties of the ambient ionospheric plasma. The charged dust is believed to be the major cause of the polar mesosphere summer echoes (PMSE). The charge of dust particles is formed by attachment of the free electrons and ions and by photo emission. The dust charge depends on the grain sizes, plasma parameters and the dust material. Recently discovered effect of the radio wave electron heating on PMSE opens new opportunities in PMC studies. We present a dynamical model of local dust charging. Rapid local heating of electrons by the high-power radio wave results in parameter-sensitive modifications of the average dust charge and free-electron density. By monitoring the dynamics of free electron density during variable radio wave heating, parameters of dusty plasma, such parameters as mean particle size, dust density properties of material, rates of photo detachment and photo ionization/detachment can be deduced. (C) 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.