Studying the relationship of localization parameters of solar sources of magnetic clouds with their characteristics and substorm activity

Abstract

We propose a method for determining location and orientation of extended solar sources of magnetic clouds, using coronagraph data and SOHO EIT/MDI images of the photosphere. To estimate the probability of formation of magnetic clouds, we use a simple cylindrical force-free model. We have established that more extended sources and those having a slight inclination to the solar equator and located on the solar limb as compared to those that are nonextended and strongly inclined can generate expanding clouds, which with high probability can reach the magnetosphere like clouds from a source near the zero meridian and low latitudes. We determine the relationship between extreme values of substorm activity and parameters of solar sources under study during the impact of magnetic clouds on Earth’s magnetosphere from the AL index. We note that there are no substorms associated with extended sources outside the heliolatitude range ~5–20°. The established relationship between solar source coordinates and geomagnetic activity of the magnetic cloud sheath and body are consistent with the most probable distribution of magnetoactive regions over the solar disk.

Keywords

• solar activity
• solar wind
• coronal plasma flow
• coronal mass ejection
• solar flare
• geomagnetic activity
• geomagnetic disturbances
• magnetosphere