|Title||Radial electric field in JET advanced tokamak scenarios with toroidal field ripple|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||K. Crombe, Y. Andrew, T.M Biewer, E. Blanco, P.C de Vries, C. Giroud, N.C Hawkes, A. Meigs, T. Tala, M. von Hellermann, K.D Zastrow|
|Journal||Plasma Physics and Controlled Fusion|
|Type of Article||Article|
|Keywords||JOINT EUROPEAN TORUS, TRANSPORT BARRIERS, TURBULENCE|
A dedicated campaign has been run on JET to study the effect of toroidal field (TF) ripple on plasma performance. Radial electric field measurements from experiments on a series of plasmas with internal transport barriers (ITBs) and different levels of ripple amplitude are presented. They have been calculated from charge exchange measurements of impurity ion temperature, density and rotation velocity profiles, using the force balance equation. The ion temperature and the toroidal and poloidal rotation velocities are compared in plasmas with both reversed and optimized magnetic shear profiles. Poloidal rotation velocity (v(theta)) in the ITB region is measured to be of the order of a few tens of km s(-1), significantly larger than the neoclassical predictions. Increasing levels of the TF ripple are found to decrease the ion temperature gradient in the ITB region, a measure for the quality of the ITB, and the maximum value of v(theta) is reduced. The poloidal rotation term dominates in the calculations of the total radial electric field (E-r), with the largest gradient in E-r measured in the radial region coinciding with the ITB.
|URL||<Go to ISI>://000265584300005|
|Alternate Title||Plasma Phys. Control. Fusion|
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