ИСТИНА

The study is devoted to the propagation of the plasma structures (that passes by the spacecraft during several minutes) through the Earth’s bow shock and magnetosheath. It is based on correlation analysis of ion density measurements. We use measurements observed simultaneously in solar wind and magnetosheath. We use ~90 hours of two THEMIS probes’ measurements in the subsolar region during 2008-2009 years and ~40 hours of THEMIS/Spectr-R measurements at distant flank during 2012-2013 years. Crosscorrelation function is calculated on 30-minutes intervals to study the modification of small-scale plasma structures. Data set includes predominantly the cases of quasi-perpendicular bow shock orientation. We find out that high value of correlation and also the absence of correlation can be observed in both regions however the correlation coefficient at flank is usually higher than the one in the subsolar region. We calculate the relative standard deviation (RSD) value of solar wind density and suggest that it is the main parameter controlling the value of correlation coefficient between solar wind and magnetosheath plasma measurements. However the solar wind density and interplanetary magnetic field (IMF) amplitude also influence on the correlation value.