Electron Screening Effects In Fusion Reactions At Low Energies

The experimental and theoretical studies of the electron screening effects in charged-particle induced reactions at energies of astrophysical interest are systematically reviewed, and the theoretical discussions on the electrostatic screening effects in the thermonuclear reactions in stellar plasma are also summarized briefly.For a deep understanding of electron screening effects, the d(d,p)t reaction has been studied in a series of deuterated metal-, insulator- and semiconductor targets using the 100kV accelerator of the Dynamitron- Tandem-Laboratorium at the Ruhr-University-Bochum. As compared to measurements performed with a gaseous D2 target, a large effect has been observed in most metals, while a comparatively small effect is found in the insulators and semiconductors. A reasonable explanation of the large effect in metals is possibly provided by the classical plasma screening of Debye applied to the quasi-free metallic electrons. The subsequent experiments are already in progress to prove this explanation. The data also provided some information on the solubility of hydrogen in the samples.