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Abstract In this study, we analyze high-spatial-resolution (0.″24) magnetograms and high-spatial-resolution (0.″10) Hαoff-band (± 0.8 Å) images taken by the 1.6 m Goode Solar Telescope to investigate the magnetic properties associated with small-scale ejections in a coronal hole boundary region from a statistical perspective. With one and a half hours of optical observations under excellent seeing, we focus on the magnetic structure and evolution by tracking the magnetic features with the Southwest Automatic Magnetic Identification Suite (SWAMIS). The magnetic field at the studied coronal hole boundary is dominated by negative polarity with flux cancellations at the edges of the negative unipolar cluster. In a total of 1250 SWAMIS-detected magnetic cancellation events, ∼39% are located inside the coronal hole with an average flux cancellation rate of 2.0 × 1018Mx Mm−2hr−1, and ∼49% are located outside the coronal hole with an average flux cancellation rate of 8.8 × 1017Mx Mm−2hr−1. We estimated that the magnetic energy released due to flux cancellation inside the coronal hole is six times more than that outside the coronal hole. Flux cancellation accounts for ∼9.5% of the total disappearance of magnetic flux. Other forms of its disappearance are mainly due to fragmentation of unipolar clusters or merging with elements of the same polarity. We also observed a number of significant small-scale ejections associated with magnetic cancellations at the coronal hole boundary that have corresponding EUV brightenings.
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This content will become publicly available on May 15, 2026
High-resolution Observations of a Small-scale Cancellation Nanoflare: Supporting Evidence for the Cancellation Nanoflare Model
Abstract An analytical cancellation nanoflare model has recently been established to show the fundamental role that ubiquitous small-scale cancellation nanoflares play in solar atmospheric heating. Although this model is well supported by simulations, observational evidence is needed to deepen our understanding of cancellation nanoflares. We present observations of a small-scale cancellation nanoflare event, analyzing its magnetic topology evolution, triggers, and physical parameters. Using coordinated observations from the Solar Dynamics Observatory and Goode Solar Telescope, we identify a photospheric flow-driven cancellation event with a flux cancellation rate of ∼1015Mx s−1and a heating rate of 8.7 × 106erg cm−2s−1. The event shows the characteristic transition fromπ-shaped to X-shaped magnetic configuration before the formation of a 2″ current sheet, closely matching model predictions. This event provides critical observational support for the cancellation nanoflare model and its role in solar atmospheric heating.
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- Award ID(s):
- 2309939
- PAR ID:
- 10598774
- Publisher / Repository:
- The Author(s). Published by the American Astronomical Society.
- Date Published:
- Journal Name:
- The Astrophysical Journal Letters
- Volume:
- 985
- Issue:
- 1
- ISSN:
- 2041-8205
- Page Range / eLocation ID:
- L11
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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