CME’s and coronal holes throw clouds of charged particles into space at very high velocities. These clouds of charged particles leave the sun with its magnetic field and can interact with the earth’s magnetic field. Figure 1 shows a CME striking the earth’s geomagnetic field.
The CME is composed of Protons, Electrons, Alpha particles and some heavier particles, and carry the sun’s magnetic field. When this material impacts the earth’s geomagnetic field, it can cause turbulence and disruptions in the ionosphere creating an Ionospheric Storm. The travel time for this material is between 1 and 3 days and its effects include depression of the Critical Frequency and increased absorption. Under severe conditions, the increased geomagnetic activity can disrupt power grids and damage satellites.
The sun constantly emits material that include Electrons, Protons and Alpha particles, and this constitutes the IMF (Interplanetary Magnetic Field). This material has a velocity that averages 360 km/sec, is highly ionized and carries with it the magnetic field of sun. Figure 2 shows the IMF heliospheric current sheet or “ballerina skirt” pattern. The earth is located within the “skirt” area and therefore is periodically subjected to both north and south polarity magnetic field solar wind. When the earth crosses a current sheet polarity boundary, a minor geomagnetic disturbance, G1 storm, maybe generated. The velocity of the solar wind varies with time and can generate a CIR, Co-rotating Interaction Region, as faster solar wind catches up with the slower wind. If the CIR generates a shock front, it can generate minor geomagnetic storm activity when this shock front hits the earth.