Observations are reported of resolved components of deuterium Balmer emission in neutral beam heated JET plasmas. The features are interpreted as Doppler-shifted emission from deuterium in the neutral beams spectrally resolved into components by the nu *B motional Stark electric field. The mechanisms of excitation of the deuterium are elucidated and the emission modelled. Attention is drawn to the diagnostic potential of the observations for measurement of local magnetic fields, deuteron density and effective plasma ion charge.

The interatomic potential determines the nuclear stopping power in materials. Most ion irradiation simulation models are based on the universal ZBL interatomic potential, which, however, is an average and hence may not describe the stopping of all ion-material combinations well. Here we consider pair-specific interatomic potentials determined experimentally and by density-functional theory simulations with the DMol approach using numerical, all-electron basis sets. The interatomic potentials calculated using the DMol approach demonstrate an unexpectedly good agreement with experimental data. Differences are mainly observed for heavy atom systems, which suggests they can be improved by extending a basis set and more accurately considering the relativistic effects. Experimental data prove that the approach of determining interatomic potentials from quasielastic scattering can be successfully used for modeling collision cascades in ion-solids collisions. The data obtained clearly indicate that the use of any universal potential is limited to internuclear distances R < 7 af (af is the Firsov length).

Particle reflection coefficients for scattering of hydrogen and deuterium atoms from amorphous beryllium, carbon and tungsten were obtained, which are of interest for thermonuclear reactor physics. For the case of deuterium scattering from tungsten the data were also calculated for polycrystalline and crystalline target. The calculations were carried out by two methods: by modeling the trajectories of the incident particles and by using the binary collision approximation. Interaction potentials between hydrogen and helium atoms and the selected materials were calculated in the scope of the density function theory using program DMol for choosing wave functions. The dependence of the reflection coefficient RN on the potential well depth was found. The results demonstrate a good agreement with the available experimental values.

This paper shows the extensions of the authors' previous work on absolute cross sections for electron capture into He+ (4l) states, produced in collisions of He2+ with atomic and molecular hydrogen, to higher impact energies (27-132 keV amu-1) than used before (2-13 keV amu-1). The cross sections have been deduced from photon emission profile measurements along the ion beam axis, detecting the He II(n=4 to n=3) radiation at a wavelength of 4686 AA. The results for collisions with atomic hydrogen generally show reasonable agreement with the atomic orbital calculations of Fritsch (1989) below 50 keV amu-1 and at the highest impact energies used (E>or=100 keV amu-1) approach the data of the distorted wave approximation by Belkic et al. (1990).

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