RADIATIVE ION-ELECTRON RECOMBINATION IN A SODIUM-SEEDED PLASMA

Photoionization cross sections or the 3p 2P1/2,3/2 state of sodium have been measured in terms of a sodium line f-value in the region between 3000 Å and 4000 Å by analysing the electron-ion recombination radiation emitted by a shock-heated sodium-seeded plasma. The results are compared with the quantum mechanical predictions of Rudkjøbing and Moskvin. The experimental cross sections are found to vary as the cube of the wave length, with an absolute magnitude of 7·2×10-18 cm2 at the continuum limit. It is shown how a knowledge of these cross sections, coupled with this experimental technique, can be used to determine unknown electron temperatures and concentrations. © 1969.