Abstract


  A TALE OF TWO SCALES: THE SOLAR CORONA

  R. Bhattacharyya, Physical Research Laboratory, ramit@prl.res.in
  S. Kumar, PRL, sanjayk@prl.res.in
  P. Smolarkiewicz, ECMWF, piotr.smolarkiewicz@ecmwf.int

The solar corona, because of its high temperature and large length scale involved, is globally characterized by large Lundquist number (S). In this limit, the condition of flux-freezing holds good, and magnetic field lines are tied to fluid parcels in their evolution. Interestingly, the large scale and as a consequence: the condition of flux-freezing; enables spontaneous development of small scales where the plasma becomes locally diffusive through a local reduction in S. Magnetic reconnection follows, the field lines are topologically rearranged and generate mass outflow and heat. In the process, the small scales decay and the flux-freezing is restored. The reconnected field lines push onto other field lines located elsewhere in the plasma and develop second generation small scales under favorable conditions, which further reconnects. This interplay between the large and the small scales, leading to repeated reconnections, is a plausibility that may shape up the dynamics of the solar corona. In this talk, we explore this plausibility through numerical computations performed in the spirit of Implicit Large Eddy Simulation (ILES).