Peter J. Catto

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Full f gyrokinetic formulations employ two gyrokinetic equations, one for ions and the other for electrons, and quasineutrality to obtain the ion and electron distribution functions and the electrostatic potential. This article shows with several examples that the long wavelength radial electric field obtained with full f approaches is extremely sensitive(More)
We derive a self-consistent equation for the turbulent transport of toroidal angular momentum in tokamaks in the low flow ordering that only requires solving gyrokinetic Fokker-Planck and quasineutrality equations correct to second order in an expansion on the gyroradius over scale length. We also show that according to our orderings the long wavelength(More)
Traditional electrostatic gyrokinetic treatments consist of a gyrokinetic Fokker-Planck equation and a gyrokinetic quasineutrality equation. Both of these equations can be found up to second order in a gyroradius over macroscopic length expansion in some simplified cases, but the versions implemented in codes are typically only first order. In axisymmetric(More)
Plasma shaping e¤ects, such as elongation, triangularity and Shafranov shift have long been considered an important ingredient in improving tokamak performance. It is known that the growth rate of ion temperature gradient (ITG) turbulence can be regulated by these shaping e¤ects and that the ITG turbulence level can also be regulated by zonal ‡ow. Moreover,(More)
The strong radial electric field in a subsonic tokamak pedestal modifies the neoclassical ion parallel flow velocity, as well as the radial ion heat flux. Existing experimental evidence of the resulting alteration in the poloidal flow of a trace impurity is discussed. We then demonstrate that the modified parallel ion flow can noticeably enhance the(More)
We highlight the necessity for evaluating and evolving the global axisymmetric radial electric field in a tokamak consistent with conservation of toroidal angular momentum for both € δf and full f gyrokinetic codes, where f is the full distribution function and € δf its departure from Maxwellian. We also consider the effects of a strong radial electric(More)
The stability of axisymmetric plasmas confined by a closed poloidal magnetic field is investigated using magnetohydrodynamic equations with anisotropic resistivity and sound waves retained. It is shown that when the system is axially and up-down symmetric and the plasma beta = (plasma pressure/magnetic pressure) is finite, a resistive instability with a(More)