Pick-up and Formation of Double Streaming Peaks of Helium Ions by Turbulent Alfven Waves in Solar Wi

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A scenario for the temperature anisotropy of heavy ions and the different streamingspeed between heavy ions and protons observed in solar wind is presented.It is demonstrated thathelium ions can be picked up by turbulent Alfven waves based on the observed wave energydensity by Helios at 0.7 AU.The physical processes for the pick-up are discussed in detail.Boththe high frequency Alfven-cyclotron waves and low frequency Alfven waves play key roles duringthe pick-up process.The kinetic characters of alpha particle from simulation results are generallyconsistent with their in situ observation properties in solar wind,such as the double streamingpeaks and asymmetry of velocity distribution along the ambient magnetic field,and the variationof the temperature anisotropy with the different stream speed between alpha particles and protons.
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