Nonlinear Processes in Geophysics The influence of solar wind turbulence on geomagnetic activity

Abstract. The importance of space weather and its forecast-ing is growing as interest in studying geoeffective processes in the Sun – solar wind – magnetosphere – ionosphere cou-pled system is increasing. In this paper higher order statis-tical moments of interplanetary magnetic field and geomag-netic SYM-H index fluctuations are compared. The proper description of fluctuations in the solar wind can elucidate im-portant aspects of the geoeffectivity of upstream turbulence and contribute to our understanding of space weather. Our re-sults indicate that quasi-stationary intervals during both quiet and stormy periods have to be investigated in order to find correlations between upstream and geomagnetic conditions. We found that the fourth statistical moment (kurtosis), which was not considered in previous studies, appears to be a new geoeffective parameter. Intermittency of the magnetic tur-bulence in the solar wind can influence the efficiency of the solar wind – magnetosphere coupling through affecting mag-netic reconnection at the Earth’s magnetopause.