The masses of CMEs measured in the inner heliosphere

Nearly 200 coronal mass ejections (CME's) detected in the Helios one and two 90 deg zodiacal light photometers, observed from 1975-1983, were catalogued. The Helios spacecraft were in sun centered orbits ranging from 0.3 to 1.0 AU. From the photometer observations of Thomson scattered sunlight in the inner heliosphere, CME masses for a subset of these events were determined using two methods: by integration of the spatial mass distribution viewed by all three photometers at a given time, and by integration of the mass flow over time past a given photometer. The 2nd method depends on CME speeds measured from timing of the peak CME brightness between the 16 deg and 31 deg photometers. This 2nd method yields two measurements of the mass for a given CME. The masses derived by the different measurements are compared. It was found that the CME excess mass values range from 10(exp 15) g to nearly 10(exp 17) g. Over the solar cycle, the results show that the mean mass per CME increases by a factor of 1.5 from solar minimum to solar maximum. The total CME mass at solar maximum is found to be about 15 percent of the total solar wind mass.