Observation of spontaneous toroidal rotation inversion in Ohmically heated Tokamak plasmas.
Bulk plasma toroidal rotation is observed to invert spontaneously from counter to cocurrent direction in TCV (Tokamak à Configuration Variable) Ohmically heated discharges, in low confinement mode, without momentum input. The inversion occurs in high current discharges, when the plasma electron density exceeds a well-defined threshold. The transition between the two rotational regimes has been studied by means of density ramps. The results provide evidence of a change of the balance of nondiffusive momentum fluxes in the core of a plasma without an external drive.
Bortolon
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Ecole Polytechnique Fédérale de Lausanne (EPFL)-Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom-Confédération Suisse, CH-1015 Lausanne, Switzerland.
Duval
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Pochelon
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Scarabosio
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