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We have measured the linear polarization of the 5016-Å, 2s 1S-3p 1P transition of Hei excited by a thin carbon foil perpendicular to the incident He+ beam at ion energies 50-500 keV. We find that the alignment of the 3p 1P term depends upon the beam current density within the range (2- 150 μA cm-2) measured. Oscillations in the dependence of both M / I (the linear polarization fraction) upon energy and the current density variation of M / I with energy are observed. We discuss possible origins of these variations.