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Peer-reviewedCC BY 4.0The Astrophysical Journal

CME Kinematics with Optical Flow: Multicoronagraph Insights into Internal Velocity Dispersion

  • Pritam Das1,2
  • Vaibhav Pant3
  • Neeraj Rathore4
4 affiliations
  1. 1Aryabhatta Research Institute of Observational Sciences
  2. 2Mahatma Jyotiba Phule Rohilkhand University
  3. 3Indian Institute of Technology Delhi
  4. 4Bareilly College
Open at sourcePDFDOICite

Abstract

Coronal mass ejections (CMEs) exhibit poorly understood internal velocity distributions. In this work, we introduce an optical flow-based method, DOFCAT (Dense Optical Flow CME Analysis Tool), applied to high-resolution data from ASPIICS/Proba-3 and METIS/Solar Orbiter to examine the internal velocity dispersion of different substructures within CMEs in the Middle Corona. We also introduce a Gaussian-tapered Fourier (GTF) filter that suppresses brightness artifacts in running-difference images from the ASPIICS wideband channel. We then apply DOFCAT to four CME events observed across ASPIICS and METIS, extracting their internal velocity information. Our results show that the velocity profiles of both the CME front and core change with position angle and are nonuniform. For impulsive CMEs, the height offset between the front and core begins to increase following the impulsive acceleration phase, while CMEs without a clear impulsive phase show a more gradual evolution of the height offset. We find that this increase in height difference occurs rapidly between 2.3 and 3.0 R ⊙ . Furthermore, the front shows a higher velocity spread than the core, with impulsiveness evident in the CME leading half. We further compute the radial self-similarity coefficient separately for the front and the core, finding that the front initially expands non-self-similarly and tends toward self-similarity at larger heights, while the core remains relatively self-similar. These findings confirm that CMEs contain complex internal flows and layered substructures within the traditional three-part morphology. Our results demonstrate the utility of DOFCAT on high-resolution coronagraphs for probing CME dynamics and provide new insights into CME initiation and evolution.

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Cite

BibTeXRIS
BibTeX
@article{das2026kinematics,
  title = {{CME Kinematics with Optical Flow: Multicoronagraph Insights into Internal Velocity Dispersion}},
  author = {Pritam Das and Vaibhav Pant and Neeraj Rathore},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = oct,
  doi = {10.3847/1538-4357/aeab8f},
  url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeab8f},
  note = {CC BY 4.0},
}
RIS
TY  - JOUR
TI  - CME Kinematics with Optical Flow: Multicoronagraph Insights into Internal Velocity Dispersion
AU  - Pritam Das
AU  - Vaibhav Pant
AU  - Neeraj Rathore
PY  - 2026
DA  - 2026/10/26
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/aeab8f
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/aeab8f
AB  - Coronal mass ejections (CMEs) exhibit poorly understood internal velocity distributions. In this work, we introduce an optical flow-based method, DOFCAT (Dense Optical Flow CME Analysis Tool), applied to high-resolution data from ASPIICS/Proba-3 and METIS/Solar Orbiter to examine the internal velocity dispersion of different substructures within CMEs in the Middle Corona. We also introduce a Gaussian-tapered Fourier (GTF) filter that suppresses brightness artifacts in running-difference images from the ASPIICS wideband channel. We then apply DOFCAT to four CME events observed across ASPIICS and METIS, extracting their internal velocity information. Our results show that the velocity profiles of both the CME front and core change with position angle and are nonuniform. For impulsive CMEs, the height offset between the front and core begins to increase following the impulsive acceleration phase, while CMEs without a clear impulsive phase show a more gradual evolution of the height offset. We find that this increase in height difference occurs rapidly between 2.3 and 3.0 R ⊙ . Furthermore, the front shows a higher velocity spread than the core, with impulsiveness evident in the CME leading half. We further compute the radial self-similarity coefficient separately for the front and the core, finding that the front initially expands non-self-similarly and tends toward self-similarity at larger heights, while the core remains relatively self-similar. These findings confirm that CMEs contain complex internal flows and layered substructures within the traditional three-part morphology. Our results demonstrate the utility of DOFCAT on high-resolution coronagraphs for probing CME dynamics and provide new insights into CME initiation and evolution.
SN  - 0004-637X
SN  - 1538-4357
ER  -