Distribution of solar energetic particles and magnetic field orientations related to strong geomagnetic storms in solar cycle 24

Based on hourly data of solar energetic particles (velocity and density), interplanetary magnetic field (IMF) Bz component, and derived IMF orientations, e.g. IMF cone angle and clock angle, we studied their relations within 155 intense geomagnetic storms (Dst index less than -100 nT) during years 2009 to 2016 of solar cycle 24. The importance of negative and southward Bz was confirmed. It is suggested that strong geomagnetic storm also depends on IMF orientation angles, especially perpendicular IMF B_z. However, strong storms is not correlated with fast proton speed, which is aligned with perpendicular or parallel IMF cone angle. In the future, we can use those derived equations for prediction of solar storm. (paper)