The seasonal variations of dielectric losses in the ionospheric plasma

ALI YESIL; IBRAHIM UNAL; ANA G. ELIAS

Malatya

Congreso; 24th International Physics Congress; 2007

Inonu University

The medium conductivity and dielectric structure determine the reflection and refraction of the radio waves. In this study, the dielectric losses of ionospheric plasma have been investigated by using the Earth?s magnetic field at both collisional and anisotropic ionospheric plasma. The dielectric coefficients of ionospheric plasma were obtained as a tensor since analytical and dielectric losses were considered as directional. The International Reference Ionosphere Model, IRI, was used in numerical calculations. The altitude profile of seasonal variations of dielectric losses has been examined for wave frequency f= 6.5 MHz, Rz=10 and  local time =1200. The dielectric losses parallel to the magnetic filed are negative up to the altitude where the refractive index is zero. The dielectric losses perpendicular to the magnetic filed are negative up to the altitude where the wave is reflected. At other altitudes it is positve. It can be said, in general, that the wave?s reflection height in the ionospheric plasma takes place where the dielectric and tangent losses change direction. Regarding seasonal variation, the dielectric losses decrease from summer to winter at the reflection heights. Losses are bigger at heights outside the reflection heights.