THE TEMPERATURE COUPLING OF IONS IN THE IONOSPHERE,

An investigation has been made of the extent to which O, He, and H ions can be considered as having a common temperature in the ionosphere. By assuming that each ion gas has its own Maxwellian velocity distribution, energy balance equations including the effects of heating by the electron gas, cooling by the neutral atmosphere, and energy coupling between the ion species have been obtained. Solutions to the energy equations for three models of the neutral atmosphere indicate that the H and He ion temperatures are higher than the O temperature in the regions between 250 and 650 km. A peak temperature difference greater than two hundred degrees occurs for H and O ions, while values between which may reach one hundred degrees are noted for the He-O sepration. An explanation of the temperature inequality has been made in terms of the atmospheric and ionospheric conditions, showing that the altitude extent of ion temperature separation increases for rising thermospheric and electron temperatures and decreases for progressively larger electron densities.