Multi-Viewpoint Observation of a Failed Prominence Eruption on the Sun

Abstract: Solar eruptions are sudden ejections of coronal mass and magnetic fields accompanied by intense energy release. The eruptive structure does not always erupt successfully, but sometimes fails to escape the Sun after initiation. The failure of an eruption, however, provides an invaluable opportunity for understanding the intricate mechanism of eruptions. We present a comprehensive observation of a failed prominence eruption on the Sun, taking advantage of multi-viewpoint and multi-messenger imaging. Simultaneous off-limb and on-disk observation gives evidence of magnetic reconnection processes occurring at different sites during the flare. Particularly, in addition to the standard flare reconnection behind the eruption, strong external reconnection occurs on the erupting flux rope, evidenced by a wealth of signatures via multi-wavelength imaging and spectroscopy. The two reconnection processes may play contrasting roles in the flux rope's acceleration and compete in altering the magnetic flux in the rope. As the high rate of external reconnection proceeds, the flux rope and embedded prominence decelerate noticeably and fail to erupt into the heliosphere, under strong magnetic confinement of overlying fields. Our results illustrate a well-defined physical picture for solar eruptive activities and provide insight into the lack of coronal mass ejections found in other solar-type stars.

• The paper details a multi-viewpoint investigation using stereoscopic and multi-messenger observations to capture the dynamics of a failed solar prominence eruption.
• It quantifies how strong overlying magnetic confinement and external reconnection decelerate the flux rope, preventing a full CME.
• The study refines flare-CME coupling models in multipolar active regions, providing insights applicable to both solar and stellar eruptive events.

Multi-Viewpoint Analysis of Failed Prominence Eruption on the Sun

Introduction

This study conducts a detailed investigation of a failed prominence eruption using stereoscopic and multi-messenger observations across a suite of solar instrumentation, including SDO/AIA, Hinode/XRT, SolO/EUI/PHI/STIX, IRIS, EOVSA, and SOHO/LASCO. The event, occurring on 2024 March 30, is characterized by an intense M9.4-class flare where the prominence and its associated flux rope exhibit an impulsive rise but ultimately fail to escape the solar corona. The analysis is framed within the context of multipolar magnetic topologies, reconnection physics, and the broader implications for CME productivity both on the Sun and other late-type stars.

Observational Overview and Event Characterization

Multi-viewpoint imaging allowed simultaneous off-limb and on-disk perspectives, providing comprehensive coverage of both coronal dynamics and photospheric/magnetospheric context. The prominence erupts from a complex, multipolar AR exhibiting four principal polarities (P1/N1 in the core, P2/N2 on the periphery). The observations capture:

• A hot flux rope structure, corroborated by EUV and SXR imaging, rising in conjunction with prominence material.
• Rapid deceleration after initiation, significant fallback of prominence mass, and absence of a coherent CME in outer coronagraph data, confirming the confined nature of the event.
• Direct evidence of various reconnection processes, with high-cadence imaging/spectroscopy elucidating temporal and spatial relationships between flare dynamics and magnetic topology.

Magnetic Configuration and Reconnection Dynamics

Potential field extrapolation of SolO/PHI-FDT magnetograms revealed a coronal X-type null point at approximately 46 Mm above the photosphere. The magnetic configuration aligns with the breakout model in multipolar systems. The event demonstrates coupled reconnection processes:

• Flare (internal) reconnection behind the erupting flux rope: Standard vertical CS under the rope, driving acceleration via poloidal flux augmentation and overlying tension reduction.
• External reconnection at the rope front: Occurring at the coronal null above the flux rope, evidenced by cusp-shaped high-temperature (10–20 MK) outflows, intense footpoint/ribbon brightenings in remote polarities, Doppler-shifted spectral signatures, and radio bursts spatially coincident with the null point.

High-resolution spectroscopy from Hinode/EIS (Fe XXIV 192.03 Å) and IRIS measured outflow velocities ($>$500 km s$^{-1}$), nonthermal broadening ($>$200 km s$^{-1}$), and reconnection rates ($M_{\mathrm{A}} \sim 0.02$–$0.2$), demonstrating fast reconnection consistent with flare/CME events. EOVSA radio imaging identified frequency-drifting coherent bursts, indicative of energetic electron acceleration in reconnection-driven topologies.

Eruption Failure: Quantitative Interpretation

Despite intense flare signatures and an impulsive rise, the flux rope failed to transition into a CME, stalling at $\sim$140–200 Mm below the critical height for torus instability ($h_{\mathrm{cr2}} \sim 180$ Mm, $n_{\mathrm{cr}}=1.5$). The analysis attributes the failure to several intertwined mechanisms:

• Strong overlying magnetic confinement: Peripheral polarities (P2/N2) possess substantially greater flux ($>$2.5 ratio), maintaining closed coronal loops and constraining vertical expansion.
• Flux rope erosion via external reconnection: The observed decrease in rope velocity, displacement of prominence threads, and transfer of material to outflow regions are consistent with direct loss of rope flux, reducing the upward hoop force and halting further acceleration.
• Reconciling competing reconnection processes: Flare reconnection supplies flux and accelerates, while the external reconnection decelerates by peeling rope flux and facilitating magnetic topological rearrangement. The timing and magnitude of these processes are tightly coupled, as evidenced by synchronized HXR/microwave peaks and abrupt changes in rope kinematics.

Theoretical and Practical Implications

The results substantiate the critical role of external reconnection, beyond the classical flare-driven paradigm, in regulating CME productivity. This provides a differentiated perspective on eruptive versus confined flare events:

• Multipolar and bipolar contexts: Similar competing reconnection processes occur at quasi-separatrix layers (QSLs) in bipolar ARs, with fate determined by the balance between internal and external flux processing.
• Stellar CME occurrence: The rarity of stellar CMEs, despite prolific flare activity, is rationalized by the potential for frequent failed eruptions under strong background fields and complex topologies, as supported by statistical studies and direct solar analogs.

Advanced multi-messenger and stereoscopic diagnostics, as shown here, are essential for unambiguously resolving magnetic dynamics, kinematic evolution, and energetic particle production in flare/CME physics.

Numerical Highlights and Claims

• The event’s external reconnection exhibits Alfvén Mach numbers reaching $^{-1}$0–$^{-1}$1, matching fast reconnection rates in intense solar flares.
• The critical overlying field ratio (P2/P1 $^{-1}$22.5) marks a regime of strong magnetic confinement, substantiating theoretical predictions (torus instability suppression).
• Prominence mass demonstrates substantial displacement and transfer, evidenced by Doppler shifts up to 200 km s$^{-1}$3, supporting direct magnetic flux erosion claims.

Broader Implications and Future Directions

The study establishes a foundation for understanding CME suppression in active stars, emphasizing the influence of large-scale field configurations and external reconnection. Future investigations will benefit from:

• Higher dynamic-range, multi-perspective imaging to track rapid topological changes and plasma diagnostics at critical reconnection sites.
• Integration of advanced MHD simulations with observational constraints to quantify flux transfer and criteria for eruption success/failure.
• Statistical analysis of stellar flare/CME correlation using combined spectroscopic and radio/microwave detection strategies.

Conclusion

This multi-viewpoint study rigorously elucidates the mechanisms underlying failed prominence eruptions in a multipolar solar AR. The event demonstrates that competing reconnection processes—internal flare reconnection enhancing flux rope acceleration and external reconnection eroding flux—play pivotal, contrasting roles. The quantitative evidence links eruption failure to both strong magnetic confinement and direct flux erosion, offering a comprehensive interpretive framework applicable to solar and stellar contexts. These insights refine models of flare-CME coupling and inform strategies for multi-wavelength solar and astrophysical eruptive event detection (2604.23084).