Correlation between the solar wind dynamic and static pressures

In this paper we examine the correlation between the solar wind dynamic and static pressures, as a function of solar cycle phase, by using the hourly data of solar wind parameters al the National Space Science Data Center OMN IWeb. The correlation is important in terms of the solar wind control of th e diameter of the distant magnetotail and other situations in which solar w ind dynamic and static pressures may separately play a role. We find that t he correlation coefficient between the two pressures is constantly high (al most always larger than 0.7) and shows little dependence on the solar cycle . Thus, even though the distant tail shape may be controlled by the static pressure of the solar wind, the shape should still be well correlated with the solar wind dynamic pressure, through the correlation between the solar wind dynamic and static pressures.