Magnetic Shocks and Substructures Excited by Torsional Alfvén Wave Interactions in Merging Expanding Flux Tubes

B. Snow, V. Fedun, F. A. Gent, G. Verth, R. Erdélyi

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)
93 Downloads (Pure)

Abstract

Vortex motions are frequently observed on the solar photosphere. These motions may play a key role in the transport of energy and momentum from the lower atmosphere into the upper solar atmosphere, contributing to coronal heating. The lower solar atmosphere also consists of complex networks of flux tubes that expand and merge throughout the chromosphere and upper atmosphere. We perform numerical simulations to investigate the behavior of vortex-driven waves propagating in a pair of such flux tubes in a non-force-free equilibrium with a realistically modeled solar atmosphere. The two flux tubes are independently perturbed at their footpoints by counter-rotating vortex motions. When the flux tubes merge, the vortex motions interact both linearly and nonlinearly. The linear interactions generate many small-scale transient magnetic substructures due to the magnetic stress imposed by the vortex motions. Thus, an initially monolithic tube is separated into a complex multithreaded tube due to the photospheric vortex motions. The wave interactions also drive a superposition that increases in amplitude until it exceeds the local Mach number and produces shocks that propagate upward with speeds of approximately 50 km s-1. The shocks act as conduits transporting momentum and energy upward, and heating the local plasma by more than an order of magnitude, with a peak temperature of approximately 60,000 K. Therefore, we present a new mechanism for the generation of magnetic waveguides from the lower solar atmosphere to the solar corona. This wave guide appears as the result of interacting perturbations in neighboring flux tubes. Thus, the interactions of photospheric vortex motions is a potentially significant mechanism for energy transfer from the lower to upper solar atmosphere.

Original languageEnglish
Article number125
Pages (from-to)1-8
JournalAstrophysical Journal
Volume857
Issue number2
DOIs
Publication statusPublished - 20 Apr 2018
MoE publication typeA1 Journal article-refereed

Keywords

  • magnetohydrodynamics (MHD)
  • shock waves
  • Sun: chromosphere
  • Sun: magnetic fields
  • Sun: oscillations

Fingerprint Dive into the research topics of 'Magnetic Shocks and Substructures Excited by Torsional Alfvén Wave Interactions in Merging Expanding Flux Tubes'. Together they form a unique fingerprint.

Cite this