[PEM12-P14] IMF dependence on solar wind parameters
Keywords:IMF, solar wind density, solar wind melocity
We studied IMF dependence upon solar wind parameters using OMNI hourly values.
Figure below is a plot of the total force (B), horizontal component (Bxy) in the ecliptic plane and vertical component (Bz) of IMF versus the solar wind density (Nsw). The IMF is averaged over 0.2/cc bin of Nsw. Data number in each bin is also plotted. The data period here is 1979-1981 (maximum SSN phase).
The figure shows (1) that B, Bxy and Bz slowly decrease with decreasing Nsw and (2) that when Nsw approaches further to zero. B and Bxy begin to increase and converges to the same finite value (about 10 nT here) while Bz converges to zero. The property (2) suggests that IMF converges to a typical spiral pattern when solar wind density converges to zero.
Two other data periods, 1999-2001 (SSN maximum) and 2007-2009 (SSN minimum) are examined. IMF observed by MAVEN orbiting Mars is also studied for the period, 2014-2018. The results of the analysis are roughly consistent with the description above. We also checked IMF dependence on solar wind velocity
Figure below is a plot of the total force (B), horizontal component (Bxy) in the ecliptic plane and vertical component (Bz) of IMF versus the solar wind density (Nsw). The IMF is averaged over 0.2/cc bin of Nsw. Data number in each bin is also plotted. The data period here is 1979-1981 (maximum SSN phase).
The figure shows (1) that B, Bxy and Bz slowly decrease with decreasing Nsw and (2) that when Nsw approaches further to zero. B and Bxy begin to increase and converges to the same finite value (about 10 nT here) while Bz converges to zero. The property (2) suggests that IMF converges to a typical spiral pattern when solar wind density converges to zero.
Two other data periods, 1999-2001 (SSN maximum) and 2007-2009 (SSN minimum) are examined. IMF observed by MAVEN orbiting Mars is also studied for the period, 2014-2018. The results of the analysis are roughly consistent with the description above. We also checked IMF dependence on solar wind velocity