title: Observation of spontaneous toroidal rotation inversion in Ohmically heated Tokamak plasmas.
abstract: 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.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL)-Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom-Confédération Suisse, CH-1015 Lausanne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Bortolon
authors.forename: B P
authors.initials: BP
authors.lastname: Duval
authors.forename: A
authors.initials: A
authors.lastname: Pochelon
authors.forename: A
authors.initials: A
authors.lastname: Scarabosio