Line Broadening Measurement in High Density Plasma I. Hα and Hβ

The profiles of H α and H β , were measured in a shock heated plasma of high electron density of 1 to 3×10 17 cm -3 . The measured profiles are compared with the theoretical ones, and some discrepancies are pointed out; the measured half width is larger than the theoretical one for H α , and the measured depth of the central dip of H β is smaller than the depth calculated by theories. The dependence of the measured depth of the dip on electron density agrees with the extrapolation from the experimental result by Wiese et at. in electron density less than 10 17 cm -3 , which indicates the effect of the ion motion. The measured value of the degree of asymmetry of H β profile, i.e., the ratio of the difference between the blue and the red peak intensity to the blue one, is approximately predicted by the theory including the effect of the quadrupole interaction between a radiating atom and the nearest ion.