Three basic types of CMEs with respect to their acceleration can be distinguished: 1) Constant-speed CMEs; 2) Accelerated CMEs; 3) Decelerated CMEs. This indicates the presence of three basic forces acting on CMEs during their propagation a) Propelling force (not well known); b) Gravity force; and c) Braking force (interaction with the background medium).
The CME angular width DCME is measured as the position angle extent of the ejecta in the sky plane. It can be also a subject to projection effect errors. DCME increases on the initial stages of propagation (< 5RSun) and then usually remains constant. Annual average DCME of non-halo CMEs range from 45° (solar minimum) to 61° (close before activity maximum) (Yashiro et al. 2004).
The latitude distribution of CMEs depends on the distribution of the closed field magnetic regions (active regions) on the solar surface. During the rising phase of solar activity cycle, CME latitudes spread gradually from those close to the equator (0°) up to all latitudes (± 90°). At the same time, the majority of eruptions are located within the average latitude interval ± Q near the equatorial plane, with Q = 60° (Gopalswamy et al. 2003).
CME occurrence rate fCME shows good correlation with the Sunspot Number (SSN). fCME peaks with a delay (about 2 years) after the peak in the SSN. This is connected to the fact that the sunspot activity is confined to the active region belt, whereas CMEs appear at all latitudes during the maximum (Gopalswamy et al. 2003, St. Cyr et al. 2000).
CME density nCME at distances ≤ 30RSun ≈ 0.14 AU is estimated from the analysis of associated with CMEs brightness enhancements in the white-light coronagraph images. At large distances (> 0.4 AU) nCME is determined from the in-situ measurements of density in MCs.
CME density dependence on the distance d from the Sun can be presented as a power-law: nCME(d) = n0(d /d0)-3.6, which with n0 = 5x105 ? 5x106 cm-3 and d0 = 3RSun gives a good approximation for the values estimated from the SoHO/LASCO coronograph images.
On the other hand, in-situ measurements of density in magnetic clouds at distances > 0.4 AU give nMC(d) = n 0MC (d / d0) (-2.4 ± 0.3) , with n 0MC = 6.47 ± 0.85 cm-3; d0 = 1 AU. Based on these data Khodachenko et al. (2007 a,b) provided combined CME density approximations (Fig.3): nminejecta(d) = 4.88 (d / d0) -2.3 and nmaxejecta(d) = 7.10 (d / d0) -3.0, where d0 = 1 AU and d is taken in AU.
Average mass of CMEs, MCME, is ≈ 1015g. Average duration of CMEs, tCME at (6 ?10) RSun is ≈ 8 hours.