DIAGNOSTICS AND OPTICAL PROPERTIES OF DENSE HELIUM PLASMAS PRODUCED IN FLASHLAMP

High pressure pulsed arcs produced in flashlamps filled with pure helium are applied for generation of dense helium plasmas characterised by temperature T ~ 2 eV and electron density n_e ~ 10¹⁸ cm⁻³. Radiative emission from flashlamps in the spectral range 300-850 run is measured and calculated taking into account a non-ideal effect due to the ionic microfield distribution (line dissolution and photorecombination threshold shift and spread) and inhomogeneity of the arc plasma. Radial profiles of temperature and particle densities are deduced from the measurements of neutral line intensities and transverse distributions of emission. The values of temperature and electron density obtained are confirmed by absorption and interferometry measurements, respectively. A good agreement between the calculated and measured spectra is obtained.