THE SOLAR-CYCLE VARIATION OF CORONAL MASS EJECTIONS AND THE SOLAR-WIND MASS FLUX

Coronal mass ejections (CMEs) are an important aspect of coronal physi cs and a potentially significant contributor to perturbations of the s olar wind, such as its mass flux. Sufficient data on CMEs are now avai lable to permit study of their longer-term occurrence patterns. Here w e present the results of a study of CME occurrence rates over more tha n a complete 11-year solar sunspot cycle and a comparison of these rat es with those of other activity related to CMEs and with the solar win d particle flux at 1 AU. The study includes an evaluation of correctio ns to the CME rates, which include instrument duty cycles, visibility functions, mass detection thresholds, and geometrical considerations. The main results are as follows: (1) The frequency of occurrence of CM Es tends to track the solar activity cycle in both amplitude and phase ; (2) the CME rates from different instruments, when corrected for bot h duty cycles and visibility functions, are reasonably consistent; (3) considering only longer-term averages, no one class of solar activity is better correlated with CME rate than any other; (4) the ratio of t he annualized CME to solar wind mass flux tends to track the solar cyc le; and (5) near solar maximum, CMEs can provide a significant fractio n (i.e., almost-equal-to 15%) of the average mass flux to the near-ecl iptic solar wind.