Generic magnetic field intensity profiles of interplanetary coronal mass ejections at Mercury, Venus and Earth from superposed epoch analyses

Abstract

We study interplanetary coronal mass ejections (ICMEs) measured by probes at different heliocentric distances (0.3-1AU) to investigate the propagation of ICMEs in the inner heliosphere and determine how the generic features of ICMEs change with heliospheric distance. Using data from the MESSENGER, Venus Express and ACE spacecraft, we analyze with the superposed epoch technique the profiles of ICME substructures, namely the sheath and the magnetic ejecta. We determine that the median magnetic field magnitude in the sheath correlates well with ICME speeds at 1 AU and we use this proxy to order the ICMEs at all spacecraft. We then investigate the typical ICME profiles for three categories equivalent to slow, intermediate and fast ICMEs. Contrary to fast ICMEs, slow ICMEs have a weaker solar wind field at the front and a more symmetric magnetic field profile. We find the asymmetry to be less pronounced at Earth than at Mercury, indicating a relaxation taking place as ICMEs propagate. We also find that the magnetic field intensities in the wake region of the ICMEs do not go back to the pre-ICME solar wind intensities, suggesting that the effects of ICMEs on the ambient solar wind last longer than the duration of the transient event. Such results provide an indication of physical processes that need to be reproduced by numerical simulations of ICME propagation. The samples studied here will be greatly improved by future missions dedicated to the exploration of the inner heliosphere, such as Parker Solar Probe and Solar Orbiter.

63 pages, 8 figures, Accepted for publication in Journal of Geophysical Research - Space physics

References in corpus (3)

• Connecting speeds, directions and arrival times of 22 coronal mass ejections from the Sun to 1 AU
• Global and local expansion of magnetic clouds in the inner heliosphere
• Preconditioning of interplanetary space due to transient CME disturbances

Cited by in corpus (18)

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• 20 Years of ACE Data: How Superposed Epoch Analyses Reveal Generic Features in Interplanetary CME Profiles
• Deriving CME density from remote sensing data and comparison to in-situ measurements
• First simultaneous in situ measurements of a coronal mass ejection by Parker Solar Probe and STEREO-A
• The effect of stream interaction regions on ICME structures observed in longitudinal conjunction
• Properties of the Sheath Regions of Coronal Mass Ejections with or without Shocks from STEREO in situ Observations near 1 AU
• Evolution of coronal mass ejections and the corresponding Forbush decreases: modelling vs multi-spacecraft observations
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• Statistical Analysis of Interplanetary Shocks from Mercury to Jupiter
• Contribution of the aging effect to the observed asymmetry of interplanetary magnetic clouds
• Plasma composition measurements in an active region from Solar Orbiter/SPICE and Hinode/EIS
• A theoretic analysis of magnetoactive GES-based turbulent solar plasma instability
• How Magnetic Erosion Affects the Drag-Based Kinematics of Fast Coronal Mass Ejections
• Evolution of coronal mass ejections with and without sheaths from the inner to the outer heliosphere -- statistical investigation for 1975-2022
• Preconditioning of the interplanetary medium due to isolated ICMEs
• Magnetic Structure and Propagation of Two Interacting CMEs from the Sun to Saturn