THE HEIGHT EVOLUTION OF THE “TRUE” CORONAL MASS EJECTION MASS DERIVED FROMSTEREOCOR1 AND COR2 OBSERVATIONS

Abstract

Using combined STEREO-A and STEREO-B EUVI, COR1, and COR2 data, we derive deprojected coronal mass ejection (CME) kinematics and CME "true" mass evolutions for a sample of 25 events that occurred during 2007 December to 2011 April. We develop a fitting function to describe the CME mass evolution with height. The function considers both the effect of the coronagraph occulter, at the beginning of the CME evolution, and an actual mass increase. The latter becomes important at about 10–15 R☉ and is assumed to mostly contribute up to 20 R☉. The mass increase ranges from 2% to 6% per R☉ and is positively correlated to the total CME mass. Due to the combination of COR1 and COR2 mass measurements, we are able to estimate the "true" mass value for very low coronal heights (<3 R☉). Based on the deprojected CME kinematics and initial ejected masses, we derive the kinetic energies and propelling forces acting on the CME in the low corona (<3 R☉). The derived CME kinetic energies range between 1.0–66 × 1023 J, and the forces range between 2.2–510 × 1014 N.