Experimental study of the electromagnetic component of drift-wave turbulence

The magnetic turbulent fluctuation spectrum is investigated in the core of a toroidally confined plasma with parameters similar to those in the fusion edge plasma. The measured spectra show fully developed turbulence over almost 6 decades down to the range of nano-Tesla field amplitudes. The magnetic fluctuations are interpreted as being due to the parallel dynamics of drift-wave turbulence. The predicted strong beta dependence of the magnetic fluctuations is experimentally confirmed. For the present parameters, anomalous transport due to the magnetic turbulence can be neglected compared with the electrostatic contribution.