Dependence of the amplitude of Pc5-band magnetic field variations on the solar wind and solar activity

摘要

We have studied the dependence of the amplitude of magnetic field variations in the Pc5 band (1.6-6.7 mHz) on the solar wind and solar activity. Solar wind parameters considered are the bulk velocity V. and the variation of the solar wind dynamic pressure 6P,. The solar activity dependence is examined by contrasting observations made in 2001 (solar activity maximum) and 2006 (solar activity declining phase). We calculated hourly Pc5 amplitude using data from geostationary satellites at L = 6.8 and ground stations covering 1 6. A radial shift of the fast mode wave turning point, associated with the solar cycle variation of magnetosphere mass density, is a possible cause of this solar activity dependence.