Observation of the Effects of Radially Sheared Electric Fields by the Use of a Gold Neutral Beam Probe

Intermittent turbulent potential fluctuations in ion-cyclotron wave heated plasmas and effects of their suppression due to strongly sheared plasma rotation with electron-cyclotron heating (ECH) for potential formation are observed in GAMMA 10. Such a shear effect on the central-cell potential data is demonstrated by the use of a heavy ion beam probe (HIBP) for the first time in GAMMA 10. The HIBP system with a gold neutral beam is employed for measuring profiles of radially formed potential as well as the associated radially sheared Er in the central cell. During the application of ECH, the produced stronger Er shear results in reduction of the turbulent fluctuations. The results are consistent with reported X-ray tomography data on the effect of Er shear on turbulence suppression.