Effects of collisional ion orbit loss on tokamak radial electric field and toroidal rotation in an L-mode plasma

Nuclear Fushion

article

Hongxuan Zhu¹  T. Stoltzfus-Dueck¹  R. Hager¹  S. Ku¹  C.S. Chang¹ 

[1] Princeton Plasma Physics Laboratory, Princeton

关键词: magnetic confinement fusion;    ion orbit loss;    gyrokinetic simulations;    radial electric field;    toroidal rotation;   

DOI  :  10.1088/1741-4326/acc815

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Ion orbit loss has been used to model the formation of a strong negative radial electric fieldE _r in the tokamak edge, as well as edge momentum transport and toroidal rotation. To quantitatively measure ion orbit loss, an orbit-flux formulation has been developed and numerically applied to the gyrokinetic particle-in-cell code XGC. We study collisional ion orbit loss in an axisymmetric DIII-D L-mode plasma using gyrokinetic ions and drift-kinetic electrons. Numerical simulations, where the plasma density and temperature profiles are maintained through neutral ionization and heating, show the formation of a quasisteady negativeE _r in the edge. We have measured a radially outgoing ion gyrocenter flux due to collisional scattering of ions into the loss orbits, which is balanced by the radially incoming ion gyrocenter flux from confined orbits on the collisional time scale. This suggests that collisional ion orbit loss can shiftE _r in the negative direction compared to that in plasmas without orbit loss. It is also found that collisional ion orbit loss can contribute to a radially outgoing (counter-current) toroidal-angular-momentum flux, which is not balanced by the toroidal-angular-momentum flux carried by ions on the confined orbits. Therefore, the edge toroidal rotation shifts in the co-current direction on the collisional time scale.

【 授权许可】

Unknown