Study of helium transport in HL-1M edge plasma region

Radial profiles of the emission intensity for H-alpha and neutral helium line (lambda = 5875.7 Angstrom) are measured to study helium transport and recycling in the HL-1M edge region in the vicinity of the poloidal graphite limiter (at r = 26 cm) after previous helium glow discharge cleaning and boronization under different LHCD and ECH conditions. A one-dimensional Monte Carlo neutral helium transport code, 1DHET, is utilized to calculate neutral helium density profile in the same region. The comparisons show that the freshly boronized wall with helium glow discharge cleaning exhibits somewhat selective recycling characteristics between the helium and hydrogen atoms, if ECH power is not applied.