I.F. Domnin, D.V. Kotov, L.F. Chernogor
Autocorrelation function of incoherent scatter signal is a complex (nonlinear) function of ionosphere plasma parameters, such as electron and ion temperatures, fractions of various sorts of ions. In turn, the values of these parameters of plasma are complicated temporal and spatial variations. In experimental studies of the ionosphere in order to ensure an acceptable level of signal/noise ratio must be used long pulses. The corresponding altitude interval occupied by the pulse, typically exceeds the characteristic altitude interval of plasma parameters values. As a result, there are methodological errors in determining the values of the temperature of ions, electrons and the fractions of ions of various sorts.
This paper presents the results of simulation of incoherent scatter signal autocorrelation functions for different heliogeophysical conditions and obtained the results of simulation of error estimates of desired ionosphere parameters values.
Simulation was performed as follows. The initial values of temperature and ion composition data used international reference ionosphere model IRI-2001. According to these data in small increments in height (about 4,5 km) with the actual equipment parameters of the radar of the Institute of Ionosphere were calculated autocorrelation functions – direct problem of radiophysics was solving. After this summation was carried out obtained autocorrelation functions for the altitude range corresponding to the real interval averaging the data processing for the Kharkov radar. In total normalized autocorrelation function are defined «measured» parameters of the plasma. The error in estimating the parameters of the plasma was determined as the difference between «measured» and simulated values.
The novelty of the research is the first time in addition to errors in estimates of temperatures of charged particles was estimated offset of values of hydrogen and helium ion fractions. The practical guidelines for organization and carrying out of ionospheric research by the incoherent scattering technique and for optimization the incoherent scattered signal analysis are formulated.