Subkilovolt x-ray radiation from an argon plasma

The x-ray spectrum between 55 and 600 eV from an argon plasma produced in the PITHON high-voltage generator has been measured using the Lockheed grating spectrograph. Below 100 eV, line shapes show a deep depression at line center. This is most likely due to Doppler shifts during implosion. Above 100 eV, broad continuous bands of radiation are observed. A simple calculational model shows that these are closely spaced, bound-bound transitions which reflect the time history of the plasma temperature.