Interplanetary propagation of Fast Coronal Mass Ejections and Shock Waves and Type II radio burst

Coronal mass ejections (CMEs) are large-scale eruptive events in the solar corona. Once they are expelled into the interplanetary (IP) medium, they propagate outwards and "evolve'' interacting with the solar wind. Fast CMEs associated with IP shocks are a critical subject for space weather investigations. We present an analytic model to study the heliocentric evolution of fast CME/shock events and their association with type II radio burst emissions. The propagation model assumes an early stage where the CME acts as a piston driving a shock wave, beyond this point the CME decelerates tending to match the ambient solar wind speed and the shock decays as a blast wave. We use the shock speed evolution and in-situ solar wind data to reproduce type II radio burst emissions. We analysed few fast CME halo events that were associated with kilometric type II radio bursts, and in-situ measurements of IP shock and CME signatures. Our analysis show that initial inertial properties of CMEs are not arbitrary but might regard relationships with the associated flare. Our results show a good agreement with the dynamic spectra of the type II frequency drifts and the in-situ measurements. This suggests that, in general, IP shocks associated with fast CMEs evolve as blast waves approaching 1 AU, implying that the CMEs do not drive their shocks any further at this heliocentric range.