Gyrokinetic analysis of radial dependence and global effects on the zero particle flux condition in a TCV plasma

In small-sized tokamaks, finite Larmor radius effects could lead to a significant discrepancy between gyrokinetic local flux-tube results and global ones. This has been highlighted by previous turbulent transport studies as in McMillan et al (2010 Phys. Rev. Lett.). The impact of such effects on the zero particle flux condition is investigated here. The zero particle flux condition is useful to estimate the density peaking, reducing the uncertainty on physical input parameters derived from experimental measurements, for cases where the particle source is negligible. This constraint has been applied to the analysis of a particular TCV discharge, where a detailed reconstruction of the zero particle flux hyper-surface in the multidimensional physical parameter space at fixed radius had been presented in Mariani et al (2018 Phys. Plasmas). Here, we extend these results, investigating their radial dependence, together with the impact of global effects. These so-called rho* effects are analyzed by simulating a plasma annulus corresponding to the stiff region 0.4 <rho(tor)< 0.8. Because of the computational cost of the nonlinear global gyrokinetic simulations, we restrict to a two species plasma in the collisionless regime, with heavy electrons and simplified density and temperature radial profiles. With these simplifications, the results seem to point towards global effects on the zero particle flux condition being relatively weak.


Published in:
Plasma Physics And Controlled Fusion, 61, 6, 064005
Year:
2019
Publisher:
IOP
ISSN:
0741-3335
1361-6587
Keywords:
Laboratories:




 Record created 2019-05-15, last modified 2019-06-27

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