RESUMO
Electron temperature fluctuations seen in a magnetically confined tokamak plasma have some of the characteristics of the avalanchelike events sometimes associated with self-organized criticality, including intermittency, large space and time scales, " 1/f" spectra, large tails in the autocorrelation function, and clear evidence of radial propagation.
RESUMO
Experimental evidence is reported of an internal kink instability driven by a new mechanism: barely trapped suprathermal electrons produced by off-axis electron cyclotron heating on the DIII-D tokamak. It occurs in plasmas with an evolving safety factor profile q(r) when q(min) approaches 1. This instability is most active when ECCD is applied on the high field side of the flux surface. It has a bursting behavior with poloidal/toroidal mode number = m/n = 1/1. In positive magnetic shear plasmas, this mode becomes the fishbone instability. This observation can be qualitatively explained by the drift reversal of the barely trapped suprathermal electrons.
