Analysis of Convective Heat Losses in JT-60U Neutral Beam Injection Experiments

The role of convective heat losses in tokamak plasmas is studied analytically and numerically. One of the natural forms of the energy confinement scaling law is suggested. The ion temperature limit in the steady-state neutral beam injection discharges caused by convective heat losses is obtained. A new technique for the determination of convective heat losses from experimental measurements is applied to the analysis of a JT-60U NBI discharge. The particle source and convective heat losses calculated directly from the experimental data are in a good agreement with ASTRA calculations. The convective heat loss obtained from the data is about 50% of the absorbed NB power.