On the Spatial Coherence of Magnetic Ejecta: Measurements of Coronal Mass Ejections by Multiple Spacecraft Longitudinally Separated by 0.01 AU

Abstract

Measurements of coronal mass ejections (CMEs) by multiple spacecraft at small radial separations but larger longitudinal separations is one of the ways to learn about the three-dimensional structure of CMEs. Here, we take advantage of the orbit of the Wind spacecraft that ventured to distances of up to 0.012 astronomical units (au) from the Sun-Earth line during the years 2000 to 2002. Combined with measurements from ACE, which is in a tight halo orbit around L1, the multipoint measurements allow us to investigate how the magnetic field inside magnetic ejecta (MEs) changes on scales of 0.005 - 0.012 au. We identify 21 CMEs measured by these two spacecraft for longitudinal separations of 0.007 au or more. We find that the time-shifted correlation between 30-minute averages of the non-radial magnetic field components measured at the two spacecraft is systematically above 0.97 when the separation is 0.008 au or less, but is on average 0.89 for greater separations. Overall, these newly analyzed measurements, combined with 14 additional ones when the spacecraft separation is smaller, point towards a scale length of longitudinal magnetic coherence inside MEs of 0.25 - 0.35 au for the magnitude of the magnetic field but 0.06 - 0.12 au for the magnetic field components. This finding raises questions about the very nature of MEs. It also highlights the need for additional "mesoscale" multi-point measurements of CMEs with longitudinal separations of 0.01 - 0.2 au.

arXiv commentPublished in ApJL, 6 pages

References in corpus (9)

• The large longitudinal spread of solar energetic particles during the January 17, 2010 solar event
• Understanding the twist distribution inside magnetic flux ropes by anatomizing an interplanetary magnetic cloud
• Interplanetary Coronal Mass Ejections observed by MESSENGER and Venus Express
• Global axis shape of magnetic clouds deduced from the distribution of their local axis orientation
• Solar cycle dependence of spatial correlation in the solar wind
• Correlation of ICME Magnetic Fields at Radially Aligned Spacecraft
• Does the spacecraft trajectory strongly affect the detection of magnetic clouds?
• Advancing In Situ Modeling of ICMEs: New Techniques for New Observations
• A Plasma β Transition Within a Propagating Flux Rope

Cited by in corpus (23)

• Validation of the Alfvén Wave Solar atmosphere Model (AWSoM) with Observations from the Low Corona to 1 AU
• Radial Evolution of Coronal Mass Ejections Between MESSENGER, Venus Express, STEREO, and L1: Catalog and Analysis
• In situ multi-spacecraft and remote imaging observations of the first CME detected by Solar Orbiter and BepiColombo
• Multipoint interplanetary coronal mass ejections observed with Solar Orbiter, BepiColombo, Parker Solar Probe, Wind and STEREO-A
• On the Mesoscale Structure of CMEs at Mercury's Orbit: BepiColombo and Parker Solar Probe Observations
• Inconsistencies Between Local and Global Measures of CME Radial Expansion as Revealed by Spacecraft Conjunctions
• First simultaneous in situ measurements of a coronal mass ejection by Parker Solar Probe and STEREO-A
• On the Radial and Longitudinal Variation of a Magnetic Cloud: ACE, Wind, ARTEMIS and Juno Observations
• A Coronal Mass Ejection and Magnetic Ejecta Observed In Situ by STEREO-A and Wind at 55${}^{\circ }$ Angular Separation
• Causes and Consequences of Magnetic Complexity Changes within Interplanetary Coronal Mass Ejections: a Statistical Study
• Evolution of interplanetary coronal mass ejection complexity: a numerical study through a swarm of simulated spacecraft
• Multi-Spacecraft Observations of the Evolution of Interplanetary Coronal Mass Ejections Between 0.3 and 2.2 AU: Conjunctions with the Juno Spacecraft
• Categorization of Coronal Mass Ejection Driven Sheath Regions: Characteristics of STEREO Events
• Turbulence Properties of Interplanetary Coronal Mass Ejections in the Inner Heliosphere: Dependence on Proton Beta and Flux Rope Structure
• On the utility of flux rope models for CME magnetic structure below 30$R_{\odot }$
• Characteristic Scales of Complexity and Coherence within Interplanetary Coronal Mass Ejections: Insights from Spacecraft Swarms in Global Heliospheric Simulations
• Small Satellite Mission Concepts for Space Weather Research and as Pathfinders for Operations
• Investigating The Cross-section of Coronal Mass Ejections Through the Study of Non-Radial Flows with STEREO/PLASTIC
• Tracking magnetic flux and helicity from Sun to Earth -- Multi-spacecraft analysis of a magnetic cloud and its solar source
• A coronal mass ejection encountered by four spacecraft within 1 au from the Sun: Ensemble modelling of propagation and magnetic structure
• New Observations Needed to Advance Our Understanding of Coronal Mass Ejections
• Space weather: the solar perspective -- an update to Schwenn (2006)
• The effects of expansion and turbulence on the interplanetary evolution of a magnetic cloud