Laboratory Observations of Plasma Satellites on the2P1−4D1and2P3−4D3Lines of Helium

Abstract

During the implosion phase of a low-density $\theta$ pinch in helium preheated to $T_e\approx 1$ eV at $N_e\approx 5\times {10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$, the He I $2{}_{}{}^1{}_{}{}^{}P-4{}_{}{}^1{}_{}{}^{}D$ and $2{}_{}{}^3{}_{}{}^{}P-4{}_{}{}^3{}_{}{}^{}D$ lines show satellites displaced away from the forbidden $2P-\mathrm{nF}$ transitions by 0.3-0.6 Å. These satellites are identified with those predicted by Baranger and Mozer as due to the effects of nonthermal longitudinal plasma oscillations on atomic spectra.