IMF cone angle control of the magnetopause location: Statistical study

We investigate the dependence of the magnetopause location on the interplanetary magnetic field (IMF) cone angle (the angle between the IMF and solar wind velocity vectors) in a statistical study based on approximate to 6500 magnetopause crossings observed by the five THEMIS spacecraft, both at the dayside and flanks. To remove other well-known effects, we analyze the difference between observed magnetopause radial distances and those predicted by an empirical magnetopause model (scalable by the solar wind dynamic pressure and IMF B-Z component). The results demonstrate a systematic increase of the magnetopause distance for radial IMF directions, from approximate to 0.3 R-E at 90 degrees to approximate to 1.7 R-E at 0 degrees or 180 degrees cone angle. Moreover, a stronger dependence of the magnetopause location on the solar wind dynamic pressure than predicted by the current models was observed. Citation: Dusik, S., G. Granko, J. Safrankova, Z. Nemecek, and K. Jelinek (2010), IMF cone angle control of the magnetopause location: Statistical study, Geophys. Res. Lett., 37, L19103, doi:10.1029/2010GL044965.