Thermal iron ions in high speed solar wind streams, 2. Temperatures and bulk velocities

Abstract

Thermal velocities vFe = (2kT/m)½ and magnetic field‐aligned bulk flow velocity increments ΔVFe = VFe ‐ VH are estimated using the recently discovered sensitivity to iron ions in high speed solar wind streams (VH > 600 kms−1) of the NOAA/JHU Energetic Particles Experiment (EPE) on IMP 7/8. Comparison with LASL hydrogen plasma measurements and GSFC magnetometer data in several recurrent streams in 1974 reveals that O ≤ ΔVFe ≲ VA and VH ≲ vFe ≲ VA where VA is the local Alfvén velocity. These relationships for iron are consistent with those found in earlier analyses of helium and oxygen and suggest that both the heating and bulk flow of heavy ions are controlled locally by wave/particle interactions.