Y. Kamiura et al., SPECTROSCOPIC STUDY OF RAPID MIXING AND COOLING OF A HIGH-DENSITY HE PLASMA-FLOW PENETRATING INTO HYDROGEN GAS, JPN J A P 1, 34(7A), 1995, pp. 3683-3688
Rapid mixing and cooling of a high-density helium plasma flow injected
into hydrogen gas was experimentally confirmed for the first time, wh
ich is essentially of importance to generate a recombining plasma as a
short-wavelength laser medium. The plasma flow was produced by a smal
l Z-pinch gun. The electron temperature and density was spectroscopica
lly measured to be 12 eV and 6 x 10(16) cm(-3), respectively, before i
njected into the hydrogen gas. After injection of the gas, the plasma
was rapidly cooled down to 4 eV while the density increased only by ab
out 30%. It was also found that the cooled plasma tended to a recombin
ing phase. A simplified calculation was also performed on the collisio
nal radiative model to show that the rapid cooling was due to the atom
ic collisions between the electrons and hydrogen atoms mixed with the
plasma.