Temperature and electron density gradient in Xe laser produced plasmas, byspectral analysis

We have performed a spectroscopic analysis on laser produced plasmas in Xe at intermediates pressures (less than 1 atm), resolved both spectrally and temporally, also discriminating different regions of the plasma. This is pr oduced by tightly focusing the radiation of a Q-switched Nd:YAG laser on a cell equipped with an observation window at right angles with respect to th e laser. Our results confirm that there is a gradient in electron density i n the plasma ball formed by the laser. This gradient almost defines at leas t two regions, an outer layer of higher electron number density, and an inn er core of lower electron number density. The electron temperature gradient has the same sign. These conclusions are supported by evidence taken using the spectral results mentioned above. (C) 2000 Elsevier Science Ltd. All r ights reserved.