Community Research and Development Information Service - CORDIS

Abstract

Anomalous transport in tokamaks is generally attributed to turbulent fluctuations. Since a large variety of modes are potentially unstable, a wide range of short-scale fluctuations should be measured, with wavenumbers from k roh(i) ~ 0.1 to k roh(i) >> 1. In the Tore Supra tokamak, a light scattering experiment has made possible fluctuation measurements in the medium and high-k domains where a transition in the k-spectrum is observed: the fluctuation level decreases much faster than usual observations, typically with a power law S(k) = k{-6}.
A scan of the ion Larmor radius shows that the transition wavenumber scales with roh(i) around k roh(i) ~ 1.5. This transition indicates that a characteristic length scale should be involved to describe the fluctuation nonlinear dynamics in this range. The resulting very low level of fluctuations at high-k does not support a strong effect of turbulence driven by the electron temperature gradient. For this gyroradius scan, the characteristics of turbulence also exhibit a good matching with predictions from gyro-Bohm scaling: the typical scale length of turbulence scales with the ion Larmor radius, the typical timescales with a/c(s); the turbulence level also scales with roh(i), according to the mixing length rule.

Additional information

Authors: HENNEQUIN P, Laboratoire de Physique et de Technologie des Plasmas, CNRS Ecole Polytechnique, Palaiseau (FR);HONORE C, Laboratoire de Physique et de Technologie des Plasmas, CNRS Ecole Polytechnique, Palaiseau (FR);TRUC A, Laboratoire de Physique et de Technologie des Plasmas, CNRS Ecole Polytechnique, Palaiseau (FR);QUEMENEUR A, Laboratoire de Physique et de Technologie des Plasmas, CNRS Ecole Polytechnique, Palaiseau (FR);SABOT R, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);HOANG G T, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);GARBET X, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);FENZI C, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: An article published in: Plasma Phys. Control. Fusion 46 (2004) 1-13 PII: S0741-3335(04)85803-2
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://www.iop.org/EJ/S/UNREG/journal/0741-3335
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top