CME Rates from 1979-1989 and Correlations With Other Solar Activity Indices

We combined coronagraph observations from Solwind and SMM to obtain monthly averages of the daily rate of coronal mass ejections (CMEs), corrected for duty cycle, for the years 1979-1989. We examined correlations between the CME rate and the following equivalent indices of solar activity: sunspot number, 10-cm quiet sun flux, and soft X-ray background flux. The CME rate exhibits significant fluctuations when compared to these other activity indices on a monthly basis; however, long-term correlations are clearly evident in each case. In early 1982 the baseline CME rate changed rapidly from a value of 1.8/day to 0.8/day; in late 1988, the reverse occurred. We note that both of these quasi-discontinuities occurred when the inclination of the heliospheric current sheet, as deduced from Stanford maps, crossed 50 degrees.