The particle source rate profile from edge to core region of the LHD (Large Helical Device) plasma is derived by a detailed analysis of the Balmer-α line of neutral hydrogen. The results are used for evaluating the particle confinement time for a plasma volume within a given magnetic flux surface, , where reff is the averaged minor radius of the flux surface. Characteristics of the particle confinement are evaluated in terms of for different conditions of the plasma. A discharge with T, where Bax is the magnetic field strength at the magnetic axis, gives s at the edge region, which is approximately one order of magnitude smaller than that of a discharge with T, while the both discharges give similar in the core region. This result confirms that the high confinement performance in the strong magnetic field discharges can be ascribed, at least in part, to a high particle confinement characteristics in the plasma edge region.
Energy confinement of beam-heated divertor and limiter discharges in Doublet III