A scenario for the temperature anisotropy of heavy ions and the different streaming speed between heavy ions and protons observed in solar wind is presented. It is demonstrated that helium ions can be picked up by turbulent Alfven waves based on the observed wave energy density by Helios at 0.7 AU. Both the high frequency Alfven-cyclotron waves and low frequency Alfven waves play key roles during the pick-up process. The kinetic characters of alpha particle from simulation results are generally consistent with their in situ observation properties in solar wind, such as the double streaming peaks and asymmetry of velocity distribution along the ambient magnetic field, and the variation of the temperature anisotropy with the different stream speed between alpha particles and protons.
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