Measurements of the argon plasma continuum: high-pressure peculiarities

The continuous emission coefficient of a high-pressure argon plasma is measured in a wall-stabilized arc in the ranges 2600 to 7000 A, 1 to 30 atm and 11200 to 13200 K. 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. (author)