6 papers
Second stability region for gyrokinetics and the L-H transition
R. J. J. Mackenbach, A. Zocco, P. Helander
Using a simple circular tokamak geometry, we show the well-known `second stability region' of MHD-ballooning modes exists for linear gyrokinetics too -- whether electrostatic or el…
Scaling laws for the cutoff wavenumber of the short-wavelength ion-temperature-gradient mode in a Z-pinch
O. Gupta, M. Barnes, F. I. Parra +4
We use a heuristic fluid model to predict the dependence of the cutoff wave number for the short-wavelength ion temperature gradient (SWITG) mode on ion density gradient, ion tempe…
Study of the impact of fast ions on core turbulence at rational surfaces via global gyrokinetic simulations
D. Brioschi, A. Di Siena, R. Bilato +6
In this work, the interplay between fast ions and safety factor rational surfaces is studied in a turbulent plasma via global nonlinear gyrokinetic simulations. Initially, the fast…
Fast electrostatic microinstability evaluation in arbitrary toroidal magnetic geometry using a variational approach
M. C. L. Morren, P. Mulholland, J. H. E. Proll +5
Small-scale turbulence originating from microinstabilities limits the energy confinement time in magnetic confinement fusion. Here we develop a semi-analytical dispersion relation…
Microtearing Turbulence and Its Role in High-Density-Gradient Plasmas in Wendelstein 7-X
H. Cu-Castillo, A. Bañón Navarro, G. Merlo +10
Gyrokinetic simulations reveal that microtearing mode (MTM) turbulence dominates transport in a Wendelstein 7-X (W7-X) discharge characterized by large density gradients, moderate…
Resonant theory of kinetic ballooning modes in general toroidal geometry
P. Mulholland, A. Zocco, M. C. L. Morren +4
The linear theory of the kinetic-ballooning-mode (KBM) instability is extended to capture a weakly-driven regime in general toroidal geometry where the destabilization is caused by…