Fusion Science and Technology / Volume 45 / Number 2T / March 2004 / Pages 362-370
Technical Paper / Plasma and Fusion Energy Physics - Anomalous Transport
The importance of radial electric fields was already recognised early in the research on controlled thermonuclear fusion. An initial description of electric field effects in toroidal confinement was given by Budker1 Such a configuration with combined magnetic and electric confinement ("magnetoelectric confinement", where the electric field provides a toroidal equilibrium configuration without rotational transform) was studied by Stix2, who suggested that a reactor-grade plasma under magnetoelectric confinement (electric fields of order 1 MV/cm) may reach a quasi-steady-state with ambipolar loss of electrons and some suprathermal ions (e.g. 3.5 MeV -particles). Experiments such as on the Electric Field Bumpy Torus EFBT3,4 provided quite favourable scaling for particle confinement. The possible importance of radial electric fields for transport was in the past repeatedly established5,6,7,8. Since the early days the plasma potential has been measured in tokamaks such as ST9, TM-410 and ISX-B11, but because no significant effects of the radial electric field Er on plasma transport were observed, no further research was conducted in tokamaks.