Investigation of non thermal effects from the Dα line wings in edge plasmas

The far wings of intense Dα lines measured at the edge of the Tore Supra Tokamak are found to exhibit a power‐law behavior. The characteristic exponent is not far from two. Since the low density rules out thermal Stark broadening, we discuss non thermal effects which may arise from the edge plasma drift‐wave turbulence. We suggest that both the Stark and the Doppler profile could be affected by the turbulence.