Statistical estimation of power deposition profile in electron cyclotron heated plasmas

The power deposition profile by modulated fundamental electron cyclotron heating is deduced with the confidence interval derived from the statistical treatment of experimental data. The second harmonic electron cyclotron emission is used for the measurement of electron temperature that is necessary in this analysis. It is shown that the resultant deposition profile is consistent with the prediction resulting from the ray tracing calculation, including the multireflection effect at the vessel wall. The local adiabatic time scale for the thermal diffusion is derived and the propriety of the time scale in the power balance analysis is confirmed. The statistical confidence interval implies a broad profile of the power absorption. The obtained results show the necessity of using the statistical approach for analysis of the experimental data. (author)