Solar cycle variation of the internal magnetic field structure of CMEs

The internal magnetic field structure of CMEs and the field structure of the solar source regions were systematically investigated during different phases of the solar cycle in cycles 19-23 based on plasma and magnetic field measurements sampled by various satellites and through multi-wavelength remote sensing observations. It is found that: 1. To first order, the internal magnetic structure of CMEs varies systematically from one solar cycle to the next with respect to the prevailing hemispheric magnetic patterns of bipolar regions following the law of hemispheric helicity dependence. 2. To second order, the field structure in CMEs varies with respect to the complex spatial evolution of the magnetic flux in the photosphere in both hemispheres over the course of the cycle itself. The two effects can naturally explain the cyclic behavior of the SN, NS variations of the internal magnetic fields in CMEs in the solar wind as well as intermittent periods of mixed distributions.