Dependence of Solar Wind Proton Temperature on the Polarization Properties of Alfvénic Fluctuations at Ion-kinetic Scales

Abstract We use fluctuating magnetic helicity to investigate the polarization properties of Alfvénic fluctuations at ion-kinetic scales in solar wind as a function β p , ratio proton thermal pressure pressure, and θ vB angle between flow local mean field, B 0 . Using almost 15 yr Wind observations, we separate contributions from with wavevectors, k quasi-parallel oblique finding that is consistent predictions linear Vlasov theory. This result suggests nonlinear turbulent these share least some Alfvén waves. also dependence temperature – plane probe for possible signatures dissipation, it correlates The parallel higher parameter space where measure right-handed fluctuations, perpendicular left-handed fluctuations. inconsistent general assumption by sampling different can analyze turbulence distribution on kB After ruling out both instrumental expansion effects, conclude our results provide new evidence importance kinetic processes depend determining wind.