Speaker
Felipe Augusto Cardoso Pereira
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1106.pdf
Turbulence suppression by electrostatic biasing in the Texas Helimak
F. A. C. Pereira1, D. L. Toufen2, Z. O. Guimarães-Filho1, I. L. Caldas1, K. W. Gentle3
1
Institute of"Physics, University of São Paulo, São Paulo, Brazil
2
Federal Institute of Education, Science and Technology of São Paulo, Guarulhos, Brazil.
3
Department of Physics and Institute for Fusion Studies, The University of Texas at
Austin, Austin, USA.
The Texas Helimak[1] is a toroidal plasma device with one-dimensional equilibrium,
magnetic curvature and shear, resembling closely the border and scrape-of layer of a
Tokamak. The Texas Helimak vacuum vessel has a rectangular cross section with 0.6 m of
internal radius, 1.6 m of external radius, and 2 m of height and the plasma is generated by
electron cyclotron resonance heating. The Helimak typical regime turbulence presents
intermittent density bursts that are responsible for an asymmetrical PDF with long tails.
This machine has four sets of plates, where Langmuir probes are mounted and from where
is possible to impose an external electrostatic bias. The electrostatic bias modify the radial
electric feld profle and change the turbulence regime, and it can even suppress the
intermittent bursts[1]. In this work, we study the conditions for the intermittent turbulence
suppression scenario by changing the density profle position in relation with the biasing
plates. We acknowledge the fnancial support of FAPESP (grants 2014/07043-0,
2015/50122-0 and 2017/23128-3).
[1] K. W. Gentle and Huang He, Plasma Sci. and Technology, 10, 284 (2008).
