Kinematics of CMEs and related shocks from LASCO data: Comparative analysis

摘要

We estimated the positions and velocities of the 10 fast limb CMEs with sources within the 30-degree from the limb and 10 fast halo CMEs with sources within the 30-degree from the solar disk center (central CMEs) using the LASCO-C2 and C3 images. The considered velocities, on which the results are based, include projection effects. We compared kinematic characteristics of the CME body with CME-related shocks whose linear projection velocities greater than 1500 km/s. For all the considered events: (1) the distance between the CME body and the related shock Delta R = (R-sh - R-b) increases with time; (2) the shock velocity V-sh is greater than the CME body velocity V-b; (3) the CME body acceleration modulus vertical bar a(b)vertical bar and the related shock acceleration modulus vertical bar a(sh)vertical bar differ. Herewith, in some cases, vertical bar a(sh)vertical bar vertical bar a(b)vertical bar, and in other cases, on the contrary, vertical bar a(sh)vertical bar vertical bar a(b)vertical bar (4) the difference in the velocities Delta V = (V-sh - V-b) grows with time for limb CMEs and decreases for central CMEs; (5) the variations of velocity-time profiles for the CME and shock are established to be equal: the velocities of both coronal structures either increase or decrease simultaneously. The following averaged values characterize the differences in the kinematics of the CME and shock: Delta R = 1.7 R-circle dot (R-circle dot is the solar radius), 'Delta V' = 250 km/s, 'V-sh/V-b' = 1.2, 'a(b)' = 65 m/s(2), 'a(sh)' = 70 m/s(2).