C M Roach et al 2009 Plasma Phys. Control. Fusion 51 124020 doi:10.1088/0741-3335/51/12/124020
C M Roach1, I G Abel2, R J Akers1, W Arter1, M Barnes1,2, Y Camenen3, F J Casson3, G Colyer1, J W Connor1, S C Cowley1, D Dickinson4, W Dorland5, A R Field1, W Guttenfelder3, G W Hammett6, R J Hastie1, E Highcock2, N F Loureiro1, A G Peeters3, M Reshko4, S Saarelma1, A A Schekochihin2, M Valovic1 and H R Wilson4
Show affiliationsThis paper reviews transport and confinement in spherical tokamaks (STs) and our current physics understanding of this that is partly based on gyrokinetic simulations. Equilibrium flow shear plays an important role, and we show how this is consistently included in the gyrokinetic framework for flows that greatly exceed the diamagnetic velocity. The key geometry factors that influence the effectiveness of turbulence suppression by flow shear are discussed, and we show that toroidal equilibrium flow shear can sometimes entirely suppress ion scale turbulence in today's STs. Advanced nonlinear simulations of electron temperature gradient (ETG) driven turbulence, including kinetic ion physics, collisions and equilibrium flow shear, support the model that ETG turbulence can explain electron heat transport in many ST discharges.
52.55.Fa Tokamaks, spherical tokamaks
Issue 12 (December 2009)
Received 29 June 2009, in final form 20 August 2009
Published 11 November 2009
C M Roach et al 2009 Plasma Phys. Control. Fusion 51 124020
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