On the cool nature of coronal nanojets

TL;DR

This paper presents a 3D simulation that models coronal nanojets, revealing their cool origin and how their properties depend on the reconnection environment, aiding understanding of coronal heating mechanisms.

Contribution

The study provides the first 3D rMHD simulation reproducing nanojet properties, offering insights into their morphology, dynamics, and detectability based on thermodynamic conditions.

Findings

Nanojets are likely cool and dense structures resulting from reconnection.

Simulation reproduces key nanojet features such as collimation and multi-wavelength visibility.

Results suggest nanojet detectability depends on the thermodynamic environment.

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.