Diagnosing the effective parameters of the ionospheric fine structure fromstatistical characteristics of radio waves in the vicinity of a regular caustic

This paper is concerned with the oblique propagation of decametric radio wa ves in the ionosphere with random electron density irregularities. Effectiv e parameters are introduced for calculating the influence of irregularities on the wave field structure. A technique is proposed for determining these parameters from measurements of statistical characteristics of the signal in the vicinity of a regular caustic. The technique uses asymptotic express ions obtained using the interference integral method and perturbation theor y, as well as matching them to the numerical solution on the basis of the m ethod of characteristics. A global semi-empirical model that is updated for current ionospheric conditions is used to specify the background medium. T he proposed technique has been tested using data from a number of mid-latit ude paths. Results obtained in this study testify that the technique deserv es a practical implementation. (C) 2001 Elsevier Science Ltd. All rights re served.