Coronal Heating: Parker Model or Turbulence, or Both?
Monday, 15 December 2014
In our previous paper [Ng et al., Astrophys. J. 747, 109, 2012], we have concluded that the Parker model of coronal heating can provide enough heating, independent of Lundquist number, for the quasi-equilibrium case with the coronal loop length L
much shorter than VAtc
, the distance travelled by Alfven waves during one correlation time of random photospheric motions. We have now generalized our simulations with cases to longer L
. We will present most recent results from a series of three-dimensional simulations based on the equations of reduced magnetohydrodynamics for the time-averaged energy dissipation rate <W
> as a function of L
. In the limit of L
, we show that <W
> is given by the photospheric Poynting flux required to launch Alfven waves. In the intermediate range of L
> is well described by a scaling based on the Kolmogorov turbulence energy cascade, rather than the Iroshnikov-Kraichnan cascade. For the whole range of L
we considered, we will show that <W
> can be modeled by combining the Parker heating and the Alfven wave launching power. This work is supported by a NSF grant AGS-0962477.