Density impact on toroidal rotation in Tore Supra: experimental observations and theoretical investigation. (4th February 2015)

• Record Type: Journal Article
• Authors: Bernardo, J; Fenzi, C; Bourdelle, C; Camenen, Y; Arnichand, H; Bizarro, João P S; Cortes, S; Garbet, X; Guimarães-Filho, Z O; Aniel, T; Artaud, J-F; Clairet, F; Cottier, P; Gunn, J; Lotte, P
• Other Names: collab.
• Is Part Of: Plasma physics and controlled fusion. Volume 57:Number 3(2015:Mar.)
• Publication Date: 2015-02-04
• Subjects: Tore Supra -- intrinsic rotation -- rotation bifurcation -- gyrokinetic calculations; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/0741-3335/57/3/035002
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: The effect of plasma density on toroidal rotation was examined in density ramp-up experiments at a plasma current of 1 MA and a toroidal magnetic field of 3.6 T in Tore Supra ohmic discharges. Experimental measurements have shown that the toroidal rotation amplitude is reduced at all radii when increasing the plasma density, although it remains in the counter-current direction. Neoclassical predictions including ripple-induced toroidal friction are in qualitative agreement with such observations. However, in the core ( r / a < 0.5) the plasma accelerates at n l ∼ 3 × 10 19 m −2 and breaks again above n l ∼ 3.5 × 10 19 m −2 . This rotation bifurcation did not appear to be correlated to a possible influence of the sawtooth activity. Nonetheless, quasi-linear gyrokinetic simulations have shown that the transition of the nature of linear microinstabilities from ITG-TEM to pure ITG occurs at n l ∼ 3 × 10 19 m −2, which could indicate a change on the turbulence driven contributions and explain the deviation from neoclassical predictions in the plasma core.