Solar wind correlation features obtained from a multi-spacecraft study

Solar wind plasma correlations are investigated using data from three widely-separated spacecraft (IMP 8, WIND, INTERBALL-1) for the years 1994–1997. The tasks of this study have been directed toward a statistical understanding of solar wind correlation behaviour. Using the large statistics for 6-hour periods (more then 2500 segments) we obtained the average plasma correlation about 0.7. The correlations were examined as a function of the solar wind ion flux, the standard deviation of the flux, and positional separations between spacecraft. It was shown that the variability of ion flux (or density) is the strongest organizational factor among the other plasma parameters. Also our data revealed that positional dependence of the solar wind plasma correlations up to 200 Re along Xse or to 100 Re along Yse or Zse is rather weak or absent.