Interaction of the Prominence Plasma within the Magnetic Cloud of an ICME with the Earth's Bow Shock

TL;DR

This study examines how prominence plasma within an ICME's magnetic cloud interacts with Earth's bow shock, revealing effects of heavy ions on shock structure and space weather implications.

Contribution

It provides new insights into the role of heavy ions in shock interactions during ICMEs, highlighting their impact on shock stability and plasma dynamics.

Findings

Heavy ions carry significant upstream energy but are less scattered at the shock.

Downstream plasma shows irregular compression due to heavy ions.

The bow shock exhibits a transition to an unstable, super Alfvénic state.

Abstract

The magnetic cloud within an interplanetary coronal mass ejection (ICME) is characterized by high magnetic field intensities. In this study, we investigate the interaction of a magnetic cloud carrying a density structure with the Earth's bow shock during the ICME event on 24 April 2023. Elevated abundances of cold protons and heavier ions, namely alpha particles and singly charged helium ions, associated with the prominence plasma are observed within this structure. The plasma downstream of the bow shock exhibits an irregular compression pattern which could be due to the presence of heavy ions. Heavy ions carry a significant fraction of the upstream flow energy; however, due to their different charge per mass ratio and rigidity, they are less scattered by the electromagnetic and electrostatic waves at the shock. We find that downstream of the shock, while the thermal ion energy is only a small fraction of the background magnetic energy density, nevertheless increased ion fluxes reduce the characteristic wave speeds in the that region. As such, we observe a transition state of an unstable bow shock layer across which the plasma flow is super Alfv\'enic in both upstream and downstream regions. Our findings help with understanding the intense space weather impacts of such events.