Observations of Instability-driven Nanojets in Coronal Loops

Sukarmadji, Ramada, Antolin, Patrick and McLaughlin, James (2022) Observations of Instability-driven Nanojets in Coronal Loops. The Astrophysical Journal, 934 (2). p. 190. ISSN 0004-637X

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Official URL: https://doi.org/10.3847/1538-4357/ac7870


The recent discovery of nanojets by Antolin et al. represents magnetic reconnection in a braided field, thus clearly identifying reconnection-driven nanoflares. Due to their small scale (500 km in width, 1500 km in length) and short timescales (<15 s), it is unclear how pervasive nanojets are in the solar corona. In this paper, we present Interface Region Imaging Spectrograph and Solar Dynamics Observatory observations of nanojets found in multiple coronal structures, namely, in a coronal loop powered by a blowout jet, and in two other coronal loops with coronal rain. In agreement with previous findings, we observe that nanojets are accompanied by small nanoflare-like intensity bursts in the (E)UV, have velocities of 150–250 km s−1 and occur transversely to the field line of origin, which is sometimes observed to split. However, we find a variety of nanojet directions in the plane transverse to the loop axis. These nanojets are found to have kinetic and thermal energies within the nanoflare range, and often occur in clusters. In the blowout jet case study, the Kelvin–Helmholtz instability (KHI) is directly identified as the reconnection driver. For the other two loops, we find that both, KHI and Rayleigh–Taylor instability (RTI) are likely to be the drivers. However, we find that KHI and RTI are each more likely in one of the other two cases. These observations of nanojets in a variety of structures and environments support nanojets being a general result of reconnection that are driven here by dynamic instabilities.

Item Type: Article
Additional Information: Funding information: P.A. acknowledges funding from his STFC Ernest Rutherford Fellowship (No. ST/R004285/2). J.A.M. acknowledges UK Science and Technology Facilities Council (STFC) support from grant ST/T000384/1. IRIS is a NASA small explorer mission developed and operated by LMSAL with mission operations executed at NASA Ames Research Center and major contributions to downlink communications funded by ESA and the Norwegian Space Center. SDO is part of NASA’s Living With a Star Program. All data used in this work are publicly available through the websites of the respective solar missions.
Uncontrolled Keywords: The Sun, Solar corona, Solar magnetic fields, Solar prominences, Magnetohydrodynamics
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 08 Aug 2022 14:31
Last Modified: 09 Aug 2022 13:45
URI: http://nrl.northumbria.ac.uk/id/eprint/49770

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