Power spectra of electron density and Boating potential fluctuations in the
velocity shear layer of the HT-GM edge region have been measured and analy
sed. All the spectra have three distinct frequency regions with the spectra
l decay indices typical of self-organized criticality systems (0, -1 and -4
) when Doppler shift effects induced by the plasma E x B how velocity have
been taken into account. These results are consistent with the predictions
of the self-organized criticality models, which may be an indication of edg
e plasma turbulence ill the HT-GM tokamak evolving into a critical state in
dependent of local plasma parameters.