HELIUM SPECTRAL LINESHAPES IN A DENSE, COOL, Z-PINCH PLASMA

Measurements of the He I 587.6 nm (2(3)P-3(3)D) fine shift-to-width ratio in a dense (1.3-3.5 x 10(24) m-3), cool (2.5-4.0 x 10(4) K) z-pinch plasma are reported. Despite difficulties imposed by the radial gradients present in this plasma, a change in the sign of the lineshift and asymmetry dependent on the density and temperature conditions was unambiguously observed. This is in qualitative agreement with recent calculations.