Multi-spacecraft study of five ICMEs and their shock waves: Helios, IMP-8 and Voyagers observations Available to Purchase

We studied the characteristics of five interplanetary coronal mass ejections (ICMEs) detected during the ascending phase of the solar cycle 21, employing simultaneous measurements of five spacecraft: Helios 1, Helios 2, IMP-8, Voyager 1, and Voyager 2. The study covers a time interval of four months (November 1977 to February 1978). We estimated different parameters of the ICMEs and their shock waves: magnetic cloud (MC) signatures, ICME and sheath radial width, ICME front velocity, total perpendicular pressure (Pt), and magnetosonic Mach number (M). In general, the ICME front velocities were slow (| V | ≈ 457km/s); but four out of the five ICMEs were preceded by shock waves. Comparing the ICME radial width registered by the Voyagers, we find a clear expansion beyond 1.5 AU. We classified the Pt profiles in three groups depending on its signature within the ejecta (G1, G2, and G3) (Russell et al. (2005)), and we correlated them with the MC signatures.