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arXiv · 2605.03055

On the cool nature of coronal nanojets

Gabriele Cozzo·Paola Testa·Juan Martinez-Sykora·Paolo Pagano·Fabio Reale·Bart De Pontieu·Viggo Hansteen·Alberto Sainz-Dalda
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Abstract

Reconnection-driven nanoflares are widely considered a leading mechanism for coronal-loop heating, but their direct fingerprints in the tenuous coronal plasma remain elusive. The recently discovered coronal nanojets offer a potential probe of reconnection dynamics, but their extreme collimation, directionality and multi-wavelength visibility are not fully understood. Here we present a 3D rMHD simulation that unprecedentedly reproduces the key properties of nanojets, offering a viable model to explain their nature. These results provide a unified picture in which nanojet morphology, dynamics and detectability are contingent on the thermodynamic environment of reconnection. Together, our results point to a cool origin of coronal nanojets, where cool and dense material permits narrow, multi-band jet signatures to emerge from reconnection.

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Gabriele Cozzo, Paola Testa, Juan Martinez-Sykora, Paolo Pagano, Fabio Reale, Bart De Pontieu, Viggo Hansteen, Alberto Sainz-Dalda. 2026-05-04. On the cool nature of coronal nanojets. https://arxiv.org/abs/2605.03055

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