Electromagnetic effects on trace impurity transport in tokamak plasmas

Journal Article · Fri Jan 15 04:00:00 EST 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3276102· OSTI ID:21344655

Hein, T; Angioni, C ^[1]

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1. Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association, D-85748 Garching bei Muenchen, 85748 Bayern (Germany)

The impact of electromagnetic effects on the transport of light and heavy impurities in tokamak plasmas is investigated by means of an extensive set of linear gyrokinetic numerical calculations with the code GYRO[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] and of analytical derivations with a fluid model. The impurity transport is studied by appropriately separating diffusive and convective contributions, and conditions of background microturbulence dominated by both ion temperature gradient (ITG) and trapped electron modes (TEMs) are analyzed. The dominant contribution from magnetic flutter transport turns out to be of pure convective type. However it remains small, below 10% with respect to the ExB transport. A significant impact on the impurity transport due to an increase in the plasma normalized pressure parameter beta is observed in the case of ITG modes, while for TEM the overall effect remains weak. In realistic conditions of high beta plasmas in the high confinement (H-) mode with dominant ITG turbulence, the impurity diffusivity is found to decrease with increasing beta in qualitative agreement with recent observations in tokamaks. In contrast, in these conditions, the ratio of the total off-diagonal convective velocity to the diagonal diffusivity is not strongly affected by an increase in beta, particularly at low impurity charge, due to a compensation between the different off-diagonal contributions.

• OSTI ID: 21344655
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 17; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CLOSED PLASMA DEVICES
ELECTROMAGNETIC FIELDS
ELECTRON MICROSCOPY
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
IMPURITIES
ION TEMPERATURE
LEPTONS
MICROSCOPY
PLASMA
PLASMA IMPURITIES
TEMPERATURE GRADIENTS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSMISSION ELECTRON MICROSCOPY
TRAPPED ELECTRONS
TURBULENCE