Hi-C 2.1 Observations of Reconnection Nanojets

TL;DR

This study reports observations of reconnection nanojets in the solar corona, analyzing their properties and dynamics, and highlights their potential role in coronal heating through detailed measurements of their speeds, lengths, and durations.

Contribution

The paper presents the first detailed observational analysis of both inward and outward reconnection nanojets using Hi-C 2.1 and SDO/AIA data, revealing their physical characteristics and correlations.

Findings

Outward jets are longer and last longer than inward jets.

Jets exhibit a wide range of speeds from subsonic to over 150 km/s.

Jets are multi-thermal, visible across multiple AIA passbands.

Abstract

One of the possible mechanisms for heating the solar atmosphere is the magnetic reconnection occurring at different spatio-temporal scales. The discovery of fast bursty nanojets due to reconnection in the coronal loops has been linked to nanoflares and considered as possible mechanism for coronal heating. The occurrence of these jets mostly in the direction inwards to the loop were observed in the past. In this study, we report ten reconnection nanojets, four with directions inward while six moving outward to the loop, in observations from High-resolution Coronal Imager 2.1 (Hi-C 2.1) and Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). We determined the maximum length, spire width, speed, and lifetimes of these jets and studied their correlations. We found that outward moving jets with higher speeds are longer in length and duration while the inward moving jets show opposite behaviour. Average duration of the outward jets is $\approx$42 s and inwards jets is $\approx$24s. We identified jets with subsonic speeds below 100 km s$^{-1}$ to high-speed over 150 km s$^{-1}$. These jets can be identified in multiple passbands of AIA extending from upper transition region to the corona suggesting their multi-thermal nature.