Edge momentum transport by neutrals: an interpretive numerical framework
Journal article, 2017

Due to their high cross-field mobility, neutrals can contribute to momentum transport even at the low relative densities found inside the separatrix and they can generate intrinsic rotation. We use a charge-exchange dominated solution to the neutral kinetic equation, coupled to neoclassical ions, to evaluate the momentum transport due to neutrals. Numerical solutions to the drift-kinetic equation allow us to cover the full range of collisionality, including the intermediate levels typical of the tokamak edge. In the edge there are several processes likely to contribute to momentum transport in addition to neutrals. Therefore, we present here an interpretive framework that can evaluate the momentum transport through neutrals based on radial plasma profiles. We demonstrate its application by analysing the neutral angular momentum flux for an L-mode discharge in the ASDEX Upgrade tokamak. The magnitudes of the angular momentum fluxes we find here due to neutrals of 0.6–2 N m are comparable to the net torque on the plasma from neutral beam injection, indicating the importance of neutrals for rotation in the edge.

Author

John Omotani

Chalmers, Physics, Subatomic and Plasma Physics

Sarah Newton

Chalmers, Physics, Subatomic and Plasma Physics

Istvan Pusztai

Chalmers, Physics, Subatomic and Plasma Physics

E Viezzer

Tünde Fülöp

Chalmers, Physics, Subatomic and Plasma Physics

Nuclear Fusion

0029-5515 (ISSN)

Vol. 57 6 066048-

Driving Forces

Sustainable development

Areas of Advance

Energy

Roots

Basic sciences

Subject Categories

Fusion, Plasma and Space Physics

More information

Created

10/7/2017