Spectral Features of Magnetic Fluctuations at Proton Scales from Fast to Slow Solar Wind

Abstract

This Letter investigates the spectral characteristics of the interplanetary magnetic field fluctuations at proton scales during several time intervals chosen along the speed profile of a fast stream. The character of the fluctuations within the first frequency decade, beyond the high frequency break located between the fluid and the kinetic regime, strongly depends on the type of wind. While the fast wind shows a clear signature of both right handed and left handed polarized fluctuations, possibly associated with KAW and Ion-Cyclotron waves, respectively, the rarefaction region, where the wind speed and the Alfvénicity of low frequency fluctuations decrease, shows a rapid disappearance of the ion-cyclotron signature followed by a more gradual disappearance of the KAWs. Moreover, also the power associated to perpendicular and parallel fluctuations experiences a rapid depletion, keeping, however, the power anisotropy in favour of the perpendicular spectrum.

10 pages, 5 figures, to be published in ApJL

References in corpus (5)

• Anisotropic scaling of magnetohydrodynamic turbulence
• Small Scale Energy Cascade of the Solar Wind Turbulence
• Radial Dependence of the Frequency Break Between Fluid and Kinetic Scales in the Solar Wind Fluctuations
• Multi-scale Hall-MHD turbulence in the solar wind
• Spectral Slope Variation at Proton Scales from Fast to Slow Solar Wind

Cited by in corpus (18)

• Nature of Kinetic Scale Turbulence in the Earth's Magnetosheath
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• Subproton-scale cascades in solar wind turbulence: driven hybrid-kinetic simulations
• Magnetic Reconnection May Control the Ion-Scale Spectral Break of Solar Wind Turbulence
• Parallel-propagating Fluctuations at Proton-kinetic Scales in the Solar Wind are Dominated by Kinetic Instabilities
• Kinetic Scale Slow Solar Wind Turbulence in the Inner Heliosphere: Co-existence of Kinetic Alfvén Waves and Alfvén Ion Cyclotron Waves
• Turbulence/wave transmission at an ICME-driven shock observed by Solar Orbiter and Wind
• The Ion Transition Range of Solar Wind Turbulence in the Inner Heliosphere: Parker Solar Probe Observations
• Anisotropies of the magnetic field fluctuations at kinetic scales in the solar wind : Cluster observations
• MHD-kinetic transition in imbalanced Alfvénic turbulence
• Proton-proton collisions in the turbulent solar wind: Hybrid Boltzmann-Maxwell simulations
• Linking Fluid and Kinetic Scales in Solar Wind Turbulence
• Anisotropy of Magnetic Field Spectra at Kinetic Scales of Solar Wind Turbulence as Revealed by Parker Solar Probe in the Inner Heliosphere
• Solar wind magnetic field background spectrum from fluid to kinetic scales
• Dependence of Solar Wind Proton Temperature on the Polarisation Properties of Alfvénic Fluctuations at Ion-kinetic Scales
• The uncertainty of local background magnetic field orientation in anisotropic plasma turbulence
• Does Turbulence along the Coronal Current Sheet Drive Ion Cyclotron Waves?
• Statistical study of electron density turbulence and ion-cyclotron waves in the inner heliosphere: Solar Orbiter observations