Perturbative Particle Transport Study in the HSX Stellarator*

Particle transport studies using modulated gas puffing have been conducted in the HSX stellarator. Transport coefficients D and V calculated from the amplitude and phase of the density modulations will be reported. The equilibrium plasma density and its modulations are measured by a multichannel interferometer system.  For data analysis, the particle source rates are modelled using both the DEGAS and EMC3-EIRENE codes. Preliminary analysis of experimental data shows that the density modulation data are fit very well with the model when using EMC3-EIRENE calculated particle source rates. The results of particle transport experiments for different plasma density, and magnetic configurations (with and without quasi-helical symmetry) are compared.