RESUMO
Up to now, the term "transport-optimized" stellarators has meant optimized to minimize neoclassical transport, while the task of also mitigating turbulent transport, usually the dominant transport channel in such designs, has not been addressed, due to the complexity of plasma turbulence in stellarators. Here, we demonstrate that stellarators can also be designed to mitigate their turbulent transport, by making use of two powerful numerical tools not available until recently, namely, gyrokinetic codes valid for 3D nonlinear simulations and stellarator optimization codes. Two initial proof-of-principle configurations are obtained, reducing the level of ion temperature gradient turbulent transport from the National Compact Stellarator Experiment baseline design by a factor of 2-2.5.
RESUMO
We consider the propagation of weakly nonlinear waves such as plasma waves, surface water waves, the interaction of laser beams with matter, particle accelerators, etc. Specifically, we study internal waves in the ocean. Hamilton's principle is used to write the fluid equations in Hamiltonian form in terms of linear eigenmode amplitudes. Numerical studies are made of the effect of Fourier grid size and resonance widths. Statistical information is generated from an ensemble of initial states of the random wave field.
