Stationary Magnetic Entropy in Ohmic Tokamak Plasmas: Experimental Evidence from the TCV Device
The electron temperature, pressure and density profiles from a large variety of Ohmically heated plasmas in TCV (Tokamak Ó Configuration Variable, B(T)<1.5T, R(0)=0.88m,a<0.25m) are compared to the theoretical predictions based on the principle of stationary magnetic entropy. These discharges include limited and diverted discharges with elongations in the range 1 to 2.54, triangularities between 0.5 and 0.72 and plasma currents in the range 0.1-1 MA. Over the entire range of quasi-stationary Ohmic conditions we observe that the sawtooth inversion radius and the electron temperature in the confinement region (outside the inversion radius), depend solely on the parameter < j > /(q0j0) where < j > is the cross sectionally averaged current density. These observed sawtooth inversion radii and the electron temperature profiles are in excellent agreement with the predictions. The stiffness of the temperature profiles implies a correlation between density and pressure profiles, which is observed in the experiment. The observed electron pressure profiles are consistent with poloidal equilibria derived by combining the stationary magnetic entropy requirement with the Grad-Shafranov-Schlueter equation, although the actually observed range of pressure profiles is smaller than the theoretically accessible one.
Bibliographic Reference: Report: LRP 669/00 (2000) 36 pp.
Availability: Available from cole Polytechnique FÚdÚrale de Lausanne (CH)
ISBN: ISSN 0458-5895
Record Number: 200012094 / Last updated on: 2000-06-23
Original language: en
Available languages: en