Solar wind structure dynamics by multipoint observations

Six-hour segments of simultaneous solar wind plasma and interplanetary magn etic field data from IMP 8, WIND and INTERBALL-1 are used to compare correl ations of the plasma and interplanetary magnetic field for the same solar w ind structures. Magnetic field structures are, on average, as well-correlat ed as plasma structures. The averaged on large statistics crosscorrelation coefficient is equal to 0.75 for ion flux and 0.71 for IMF magnitude compar ison. But for many individual 6-hour segments the difference between plasma and IMF correlations is rather large. We find that good IMF correlations coincide with good plasma correlations 6 5% of the time but that good plasma correlations coincide with good IMF cor relations only 44% of the time. Also the dependence of ion flux correlations on the IMF cone angle was stud ied for two sets of data. The plasma correlations increase as the IMF cone angle increases, suggesting plasma structures may be elongated parallel to the IMF. (C) 1999 Elsevier Science Ltd. All rights reserved.