1 research outputs found
Dynamics of braided coronal loops: II. Cascade to multiple small-scale reconnection events
Aims. Our aim is to investigate the resistive relaxation of a magnetic
loop that contains braided magnetic flux but no net current or helicity. The loop is
subject to line-tied boundary conditions. We investigate the dynamical processes that
occur during this relaxation, in particular the magnetic reconnection that occurs, and
discuss the nature of the final equilibrium.
Methods. The three-dimensional evolution of a braided magnetic field is
followed in a series of resistive MHD simulations.
Results. It is found that, following an instability within the loop, a
myriad of thin current layers forms, via a cascade-like process. This cascade becomes more
developed and continues for a longer period of time for higher magnetic Reynolds number.
During the cascade, magnetic flux is reconnected multiple times, with the level of this
“multiple reconnection” positively correlated with the magnetic Reynolds number.
Eventually the system evolves into a state with no more small-scale current layers. This
final state is found to approximate a non-linear force-free field consisting of two flux
tubes of oppositely-signed twist embedded in a uniform background field