Transverse MHD waves as signatures of braiding-induced magnetic reconnection in coronal loops

Fuente: arXiv
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Main Authors: Sukarmadji, A. Ramada. C., Antolin, Patrick
Format: Preprint
Published: 2024
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author Sukarmadji, A. Ramada. C.
Antolin, Patrick
author_facet Sukarmadji, A. Ramada. C.
Antolin, Patrick
contents A major coronal heating theory based on magnetic reconnection relies on the existence of braided magnetic field structures in the corona. In this small-angle reconnection scenario, numerical simulations indicate that the reconnected magnetic field lines are driven sideways by magnetic tension and can overshoot from their new rest position, thereby leading to low-amplitude transverse MHD waves. This provides an efficient mechanism for transverse MHD wave generation, and the direct causality also constitutes substantial evidence of reconnection from braiding. However, this wave-generation mechanism has never been directly observed. Recently, the telltale signature of small-angle reconnection in a sheared coronal structure has been identified through nanojets, which are small, short-lived, and fast jet-like bursts in the nanoflare range transverse to the guide-field. We present for the first time IRIS and SDO observations of transverse MHD waves in a coronal loop that directly result from braiding-induced reconnection. The reconnection is identified by the presence of nanojets at the loop apex which release nanoflare-range energy. We find that the oscillations have an energy flux on the order of $10^6 - 10^8$~erg~cm$^{-2}$~s$^{-1}$, which is within the budget to power active region loops. The estimated kinetic and thermal energy from the nanojets is also sufficient to power the transverse waves and sustain the observed heating at the loop apex. This discovery provides major support to (a) existing theories that transverse MHD waves can be a signature of reconnection, (b) the existence of braiding in coronal structures and (c) the coronal reconnection scenario identified by nanojets.
format Preprint
id arxiv_https___arxiv_org_abs_2401_07678
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transverse MHD waves as signatures of braiding-induced magnetic reconnection in coronal loops
Sukarmadji, A. Ramada. C.
Antolin, Patrick
Solar and Stellar Astrophysics
A major coronal heating theory based on magnetic reconnection relies on the existence of braided magnetic field structures in the corona. In this small-angle reconnection scenario, numerical simulations indicate that the reconnected magnetic field lines are driven sideways by magnetic tension and can overshoot from their new rest position, thereby leading to low-amplitude transverse MHD waves. This provides an efficient mechanism for transverse MHD wave generation, and the direct causality also constitutes substantial evidence of reconnection from braiding. However, this wave-generation mechanism has never been directly observed. Recently, the telltale signature of small-angle reconnection in a sheared coronal structure has been identified through nanojets, which are small, short-lived, and fast jet-like bursts in the nanoflare range transverse to the guide-field. We present for the first time IRIS and SDO observations of transverse MHD waves in a coronal loop that directly result from braiding-induced reconnection. The reconnection is identified by the presence of nanojets at the loop apex which release nanoflare-range energy. We find that the oscillations have an energy flux on the order of $10^6 - 10^8$~erg~cm$^{-2}$~s$^{-1}$, which is within the budget to power active region loops. The estimated kinetic and thermal energy from the nanojets is also sufficient to power the transverse waves and sustain the observed heating at the loop apex. This discovery provides major support to (a) existing theories that transverse MHD waves can be a signature of reconnection, (b) the existence of braiding in coronal structures and (c) the coronal reconnection scenario identified by nanojets.
title Transverse MHD waves as signatures of braiding-induced magnetic reconnection in coronal loops
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2401.07678