Patrick Diamond  ,   University of California, San Diego

The Taylor hypothesis posits that a system in a state of MHD turbulence will relax so as to minimize
its magnetic energy subject to the constraint of conserved global magnetic helicity.
A simple model of the dynamics of Taylor relaxation is derived from the basic MHD equations using symmetry principles alone.
The model constrains the form of the turbulent helicity flux, but no statistical closure approximations are invoked,
and no detailed plasma model properties are assumed.
The model yields a one space (i.e. radius) - one time dimensional pde for excursions of the current profile from the Taylor state.
Notably, the model predicts several classes of non-diffusive helicity transport phenomena, including traveling nonlinear waves and super-diffusive turbulent pulses.
A 'universal' structure for the scaling of the effective turbulent magnetic Reynolds number of a system undergoing Taylor relaxation is derived.
Some basic properties of intermittency in helicity transport are examined.
Numerical solutions of the model equation and extensions beyond the MHD model will be discussed.