Measurements of the argon plasma continuum: high-pressure peculiarities

The continuum emission coefficient of a high-pressure argon plasma is measured in a wall-stabilized arc in the ranges 2600-7000 AA, 1-30 atm and 11200-13200K. The temperature and the electron density are determined independently using standard spectroscopic methods. Results of continuum measurements are compared with resultant calculated values of free-bound and both electron-ion and electron-neutral free-free radiation. The discrepancies existing at high pressure cannot be entirely explained by a shift of recombination thresholds.