10 papers
Control of the bootstrap current in approximately quasi-axisymmetric magnetic fields
J. L. Velasco, I. Calvo, J. M. GarcÃa-Regaña
Quasi-axisymmetric stellarators are the stellarator analogue of the axisymmetric tokamak, retaining many of its favorable confinement properties, its compacity and its relative coi…
Strong gradient neoclassical transport in the plateau regime
Silvia Trinczek, Felix I. Parra, Peter J. Catto +1
Strong gradient regions in tokamaks such as the pedestal or internal transport barriers are regions of reduced turbulence where neoclassical transport can play a dominant role. In…
Combination of quasi-isodynamic and piecewise omnigenous magnetic fields
J. L. Velasco, I. Calvo, V. Fernández-Pacheco +5
Due to their simultaneous optimization for radial and parallel neoclassical transport, quasi-isodynamic fields have been the main choice of stellarator magnetic configuration for m…
Role of the radial electric field in the confinement of energetic ions in the Wendelstein 7-X stellarator
M. Arranz, J. L. Velasco, I. Calvo +1
Good fast-ion confinement is an essential requirement for a fusion reactor. The magnetic configuration of the Wendelstein 7-X (W7-X) stellarator is partially optimized in this rega…
CIEMAT-QI4X: a reactor-relevant quasi-isodynamic stellarator configuration compatible with an island divertor
E. Sánchez, J. L. Velasco, I. Calvo +3
A four-field-period quasi-isodynamic stellarator configuration is presented that exhibits small neoclassical and electrostatic turbulent transport, good fast-ion confinement over a…
Modification of ion-temperature-gradient turbulence by impurities in stellarator plasmas
Ivan Calvo, Felix I. Parra, Hanne Thienpondt +1
Recent nonlinear gyrokinetic simulations have shown that impurities can strongly modify the turbulent heat flux in stellarator plasmas. Here, the ion-temperature-gradient (ITG) dis…