SMuK 2023 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 4: HEPP II

P 4.3: Vortrag

Montag, 20. März 2023, 17:20–17:45, CHE/0091

Non-local neoclassical PIC simulations for the radial electric field in stellarators. — •Michał Kuczyński, Ralf Kleiber, and Håkan Smith — Max-Planck-Institut für Plasmaphysik, Greifswald, Germany

Transport in fusion plasma devices can be classified as either turbulent or neoclassical. While turbulence is responsible for the majority of particle and heat losses in both, tokamaks and optimised stellarators the theory of neoclassical transport should not be disregarded. Its applications, for example the prediction of the bootstrap current, are of great importance in fusion research. This talk focuses on the neoclassical radial electric field in stellarators.

For a quasi-neutral plasma in a thermodynamic equilibrium, commonly, the electric field is negative throughout the plasma vessel. This is called an ion root. However, when electrons are much hotter than ions, the electric field takes a positive value. This electron root and can be achieved with, for example, ECRH heating. As correctly predicted by the local neoclassical transport theory, this is a consequence of the ambipolarity condition on the ion and electron fluxes. However, the theory meets its limitations when there is a transition between the two solutions. Moreover, since the electric field switches the sign during the transition, the strongly sheared ExB flow is likely to affect turbulence. To understand the physics of this phenomenon we must resort to simulations of global neoclassical transport. We present the first self-consistent global neoclassical radial electric field simulations performed using a particle-in-cell code - EUTERPE.