3D numerical transport study of the edge ergodized plasma in TEXTOR-DED

Abstract

Transport properties of the edge ergodized plasma in TEXTOR-DED (Finken K H and Wolf G H 1997 Fusion Eng. Des. 37 337) are studied using the 3D plasma edge transport code package, EMC3-EIRENE, prior to the forthcoming experimental campaign. EMC3 solves the steady-state plasma fluid equations of mass, momentum and energy, in almost any arbitrary 3D magnetic and bounding surface configurations. It is iteratively coupled with EIRENE, a 3D kinetic neutral particle transport code. Two different levels of ergodization have been selected in order to assess the additional effects of ergodicity on edge plasma transport. The code predicts a significant change in the radial profile of electron temperature for the higher ergodization and a pronounced correlation between the plasma flow fields and the magnetic field structure. The role of the (outermost) 'laminar zone' on the energy deposition pattern onto the divertor is analysed. It is found that its influence depends sensitively on the degree of ergodization achieved.

Helical modulation of the electrostatic plasma potential due to edge magnetic islands induced by resonant magnetic perturbation fields at TEXTOR

“…We considered temperature T e = 90 eV and T i = 100 eV and thermal collisions with a background at density n e = 8.7 × 10 12 cm −3 . These values are chosen to approximate the experiment conditions and calculated through the transport code EMC3-Eirene [55] in unperturbed conditions. The area of the domain is an Archimedes' serpentine, namely, a cyclic helical surface generated by the helical motion of a circle, whose area is A = 4π 2 b r 2 s + R 2 q 2 .…”

Effects of the Stochasticity on Transport Properties in High-β LHD

“…To estimate the radial diffusion using the mean squared displacement, the definition of the radial coordinate is very important. In tokamak studies of the Dynamic Ergodic Divertor (DED) [12,13], the radial coordinate is defined by 2D MHD equilibrium field because they use the vacuum approximation, which is 2D MHD equilibrium superposed the perturbed field for the vacuum. It is an easy way to calculate the radial displacement.…”

Free energy minimization approach to penetration of resonant magnetic perturbations in tokamaks

“…[5][6][7][8][9][10][11][12][13][14] Diverse mechanisms of the RMP effect on transport processes revealed in these studies rely significantly on the level of the perturbation amplitude in the edge plasma. Thus, in many investigations [13][14][15][16][17] the vacuum approximation considering the total magnetic field in the plasma region as a sum of the axisymmetric confinement field and the vacuum field induced by the external coils has been applied. This approximation neglects, however, a possible screening of the RMP field and the related change in the magnetic field topology.…”