Practical gyrokinetics

AstroGK: Astrophysical gyrokinetics code

Limitations, Insights and Improvements to Gyrokinetics

For a tokamak, we consider gyrokinetic quasineutrality limitations when evaluating the axisymmetric radial electric field; provide an insight by considering the gyrokinetic entropy production restriction on an ion temperature pedestal like that of ITER; and an present an improved hybrid gyrokinetic-fluid treatment valid on slowly evolving transport time scales.

Limitations of Gyrokinetics on Transport Time Scales

We present a new recursive procedure to find a full f electrostatic gyrokinetic equation correct to first order in an expansion of gyroradius over magnetic field characteristic length. The procedure provides new insights into the limitations of the gyrokinetic quasineutrality equation. We find that the ion distribution function must be known at least to second order in gyroradius over character...

Reduction and approximation in gyrokinetics

The gyrokinetics formulation of plasmas in strong magnetic fields aims at the elimination of the angle associated with the Larmor rotation of charged particles around the magnetic field lines. In a perturbative treatment or as a time-averaging procedure, gyrokinetics is in general an approximation to the true dynamics. Here we discuss the conditions under which gyrokinetics is either an approxi...

Non-Physical Momentum Sources in Slab Geometry Gyrokinetics

We investigate momentum transport in the Hamiltonian electrostatic gyrokinetic formulation in Dubin D H E et al [1983 Phys. Fluids 26 3524]. We prove that the long wavelength electric field obtained from the gyrokinetic quasineutrality introduces a non-physical momentum source in the low flow ordering. PACS numbers: 52.30.Gz, 52.35.Ra, 52.65.Tt Submitted to: Plasma Phys. Control. Fusion Non-phy...