Flux-loss of buoyant ropes interacting with convective flows

¹ The Royal Swedish Academy of Sciences, Stockholm Center for Physics, Astronomy and Biotechnology, 10691 Stockholm, Sweden
² Space Sciences Laboratory, University of California, Berkeley, CA-94720-7450, USA
³ The Niels Bohr Institute for Astronomy, Physics and Geophysics, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark

Corresponding author: S. B. F. Dorch, dorch@astro.su.se

Received: 27 August 2001
Accepted: 2 October 2001

Abstract

We present 3-d numerical magneto-hydrodynamic simulations of a buoyant, twisted magnetic flux rope embedded in a stratified, solar-like model convection zone. The flux rope is given an initial twist such that it neither kinks nor fragments during its ascent. Moreover, its magnetic energy content with respect to convection is chosen so that the flux rope retains its basic geometry while being deflected from a purely vertical ascent by convective flows. The simulations show that magnetic flux is advected away from the core of the flux rope as it interacts with the convection. The results thus support the idea that the amount of toroidal flux stored at or near the bottom of the solar convection zone may currently be underestimated.