Time evolution of the exponential wavenumber spectra of turbulence upon helium injection into a hydrogen discharge at the FT-2 tokamak
- Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)
The effect of variations in the key parameter of short-wavelength turbulence-the ion-acoustic Larmor radius {rho}{sub s}, which determines the position of the maximum of the drift instability growth rate over poloidal wavenumbers-was studied experimentally at the FT-2 tokamak. For this purpose, helium was injected to hydrogen plasma, which resulted in a change in the electron temperature at the plasma edge. The universality of the exponential shape of the turbulence spectra over radial wavenumbers q and a substantial excess of the characteristic turbulence scale L over the ion-acoustic Larmor radius was confirmed with the help of correlative diagnostics of enhanced scattering. This excess at the discharge periphery reaches a value of 3-5 at a low electron temperature, apparently, due to an increase in the dissipation of drift waves upon their cascade transfer toward short scale-lengths.
- OSTI ID:
- 22126532
- Journal Information:
- Plasma Physics Reports, Vol. 39, Issue 5; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-780X
- Country of Publication:
- United States
- Language:
- English
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