title: Constraining Solar Wind Heating Processes by Kinetic Properties of Heavy Ions.
abstract: We analyze the heavy ion components (A>4  amu) in collisionally young solar wind plasma and show that there is a clear, stable dependence of temperature on mass, probably reflecting the conditions in the solar corona. We consider both linear and power law forms for the dependence and find that a simple linear fit of the form T_{i}/T_{p}=(1.35±.02)m_{i}/m_{p} describes the observations twice as well as the equivalent best fit power law of the form T_{i}/T_{p}=(m_{i}/m_{p})^{1.07±.01}. Most importantly we find that current model predictions based on turbulent transport and kinetic dissipation are in agreement with observed nonthermal heating in intermediate collisional age plasma for m/q<3.5, but are not in quantitative or qualitative agreement with the lowest collisional age results. These dependencies provide new constraints on the physics of ion heating in multispecies plasmas, along with predictions to be tested by the upcoming Solar Probe Plus and Solar Orbiter missions to the near-Sun environment.
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tracy
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Justin C
authors.initials: JC
authors.lastname: Kasper
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Jim M
authors.initials: JM
authors.lastname: Raines
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Shearer
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Gilbert
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Zurbuchen