MeerKAT reveals three electron acceleration sites in one solar flare

MeerKAT reveals three electron acceleration sites in one solar flare Sadie Harley Scientific Editor Robert Egan Associate Editor Solar flares are the most explosive energy-release events in the solar corona, leading to intense particle acceleration, plasma heating and bulk plasma motions on short timescales. Core questions during solar flares remain unresolved, including how and where particle acceleration occurs, and how energized electrons propagate through coronal magnetic structures. Radio observations, due to their unique sensitivity to nonthermal and thermal electrons, serve as powerful diagnostics of electron dynamics and high-temperature plasma in the low corona. However, these diagnostics have long been constrained by instrumental limitations. Obtaining radio imaging spectroscopy with sufficient fidelity, dynamic range and spatial resolution to disentangle faint, diffuse emission from bright, rapidly varying bursts across a wide frequency range has been particularly challenging. A paper in The Astrophysical Journal Letters presents, for the first time, detailed high-fidelity imaging spectroscopy of a solar flare using MeerKAT, a powerful radio interferometric array in South Africa and a precursor to the Square Kilometer Array (SKA), SKA-Mid. The study focuses on a GOES M1.3-class flare in the 0.8–1.7 GHz range and takes advantage of MeerKAT's excellent sensitivity and uv-coverage. Multiple sources come into view The observations achieve an unprecedented dynamic range exceeding 1,000 across multiple frequencies, enabling the simultaneous imaging of intense coherent bursts and faint, spatially extended incoherent emission from the same active region. This addresses a long-standing challenge in solar flare radio diagnostics: the inability to observe both bright and faint emission components simultaneously. The observations reveal three coherent radio sources located in different parts of the flaring region, each associated with distinct populations of accelerated electrons. This spatial multiplicity suggests that, rather than a single dominant acceleration site, the flare energizes electrons in multiple magnetic structures, consistent with a fragmented or temporally intermittent reconnection environment. Spectroscopic imaging enables the construction of spatially resolved vector dynamic spectra, allowing each source to be analyzed independently in time and frequency. The sources exhibit markedly different spectral behaviors, reflecting distinct electron dynamics. By combining the radio observations with magnetic field extrapolations, the locations of these sources can be linked to specific coronal magnetic structures, allowing the dynamics of accelerated electrons to be interpreted within the specific magnetic topology. Diffuse emission broadens the picture Beyond the bright coherent bursts, MeerKAT also detects faint and diffuse incoherent radio emission that extends beyond the structures visible in ultraviolet. This implies the presence of hot, low-density plasma that is effectively invisible to standard EUV diagnostics. This result has important implications for flare energy partition: Thermal energy stored in tenuous plasma may be underestimated in EUV-only analyses, potentially biasing our understanding of flare energetics. The interpretation is further strengthened by combining the radio observations with co-temporal hard X-ray imaging, which traces bremsstrahlung emission from high-energy electrons, and magnetic field extrapolations that provide the three-dimensional coronal context. In summary, the multi-frequency, multi-instrument analysis anchors the coherent radio sources within distinct magnetic structures, reinforcing the conclusion that the observed components arise from different acceleration or trapping regions rather than from projection effects or imaging artifacts. Such cross-validation has been largely absent in previous radio flare studies. These results demonstrate that MeerKAT represents a significant advance in investigating spatially distinct emission sources and their associated energetic electrons, substantially strengthening diagnostic capabilities when combined with EUV and hard X-ray observations. Multiple spatially distinct coherent sources reveal different populations of accelerated electrons associated with separate magnetic structures, consistent with the possibility of fragmented or multi-site reconnection. The detection of diffuse incoherent emission extending beyond EUV-visible structures suggests that MeerKAT can probe hot, low-density plasma that is not accessible to EUV instruments, offering new insights into flare energy partition and particle transport. Publication details Yingjie 英杰 Luo 骆 et al, First Detailed MeerKAT Imaging Spectroscopy of a Solar Flare, The Astrophysical Journal Letters (2026). DOI: 10.3847/2041-8213/ae42c1 Journal information: Astrophysical Journal Letters Provided by Community of European Solar Radio Astronomers