Modeling Interplanetary Expansion and Deformation of CMEs with ANTEATR-PARADE I: Relative Contribution of Different Forces

TL;DR

This paper introduces ANTEATR-PARADE, an advanced CME model that incorporates physics-driven size and shape changes, internal forces, and asymmetries to improve predictions of CME properties and impacts.

Contribution

The paper presents ANTEATR-PARADE, a new CME model that includes detailed physics of size, shape, and force interactions, enhancing realism over previous models.

Findings

CME cross section and axis pancaking observed in simulations

Initial velocities, drag, and thermal expansion significantly influence CME evolution

Model shows reduced sensitivity to axial forces and specific cross section expansion forms

Abstract

Coronal Mass Ejections (CMEs) are key drivers of space weather activity but most predictions have been limited to the expected arrival time of a CME, rather than the internal properties that affect the severity of an impact. Many properties, such as the magnetic field density and mass density, follow conservation laws and vary systematically with changes in the size of a CME. We present ANTEATR-PARADE, the newest version of the ANTEATR arrival time model, which now includes physics-driven changes in the size and shape of both the CME's central axis and its cross section. Internal magnetic and thermal and external drag forces affect the acceleration of the CME in different directions, inducing asymmetries between the radial and perpendicular directions. These improvements should lead to more realistic CME velocities, both bulk and expansion, sizes and shapes, and internal properties. We present the model details, an initial illustration of the general behavior, and a study of the relative importance of the different forces. The model shows a pancaking of both the cross section and central axis of the CME so that their radial extent becomes smaller than their extent in the perpendicular direction. We find that the initial velocities, drag, any form of cross section expansion, and the precise form of thermal expansion have strong effects. The results are less sensitive to axial forces and the specific form of the cross section expansion.