Effects of D-region RF heating studied with the Sodankylä Ion Chemistry model

• Main Authors: Enell, C.-F., Kero, A., Turunen, E., Ulich, Th., Verronen, P. T., Seppälä, A., Marple, S., Honary, F., Senior, A.
• Other Authors: Sodankylä Geophysical Observatory, University of Oulu, Finnish Meteorological Institute (FMI), Lancaster University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Kilpisjärvi; Norway; Sodankylä; Tromsø; EISCAT
• Online Access: https://hal.science/hal-00317809; https://hal.science/hal-00317809/document; https://hal.science/hal-00317809/file/angeo-23-1575-2005.pdf

International audience The upper mesosphere and lower thermosphere, or ionospheric D region, is an atmospheric layer which is difficult to access experimentally. A useful method that also has a large potential for further studies is artificial heating of electrons by means of powerful radio transmitters. Here we estimate the effect of D-region heating for a few typical cases of high electron density ? daylight, typical auroral electron precipitation, and a solar proton event ? by coupling a model of RF electron heating to the Sodankylä Ion Chemistry (SIC) model. The predicted effects are among others an increase in the ratio of the concentration of negative ions to that of free electrons, and an increase in the absorption of cosmic noise as measured by riometers. For the model runs presented in this paper we have calculated the absorption for the frequency (38.2MHz) of the IRIS imaging riometer in Kilpisjärvi, Finland, as observing the ionosphere above the EISCAT Heater in Tromsø, Norway. The predicted enhancements of the absorption are 0.2?0.8dB, an effect which is clearly detectable. Keywords. Ionosphere (Active experiments; Ion chemistry and composition; Wave propagation)