Numerical-analytical modeling of refraction of the low-frequency solar radio-bursts in perturbed crown

Instrument of numerical-analytical modeling is offered for estimation of influence of solar crown on the trajectory characteristics and spatial weakening of low-frequency solar radio-bursts. Key function of instrument is numerical integration of the system of light differential equations expanded equations for calculation of beam divergence. Analytical models of coronal plasma are employed as models of dielectric constant of the medium. Precisesolutions for easy model are obtained for testing of calculation. Comparison of results of numerical and analytical calculations demonstrated high accuracy of numerical integration. The offered instrument of numerical-analytical modeling can be used for analyze of the refraction characteristics of the low-frequency solar radio-bursts in perturbed heliophysical conditions. Features of propagation of radio-bursts in presence coronal mass ejection (CME) are identified. It is shown that significant increase of way appears for behind-the-limb localization of source at defined sector of initial angles of radiation. Such effect occurs because of waveguide mechanism of propagation on radio-emission in channel formed in cavity of CME. Calculations of spatial weakening of behind-the-limb radio-burst for various parameters of CME and coronal plasma are performed. The presence of perturbation of low concentration at crown contributes appearance of low- frequency radio-burst of the behind-the-limb source, which can be registered on orbit of Earth by ground-based means of observation. On the basis of numerical-analytical modeling it is shown that the behind-the-limb low-frequency radio-bursts can be used for diagnostics of solar crown and estimation of parameters of CME.