Redcoats

Howes, Frank; Winstock, Lewis S.

doi:10.2307/956541

Cited by 1 publication

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…KAWs have been found in many in situ spacecraft measurements (Chaston et al 2008;Chaston et al 2009;Huang et al 2012;Podesta 2013). Identification of KAWs is usually accomplished by analyzing characteristic wave parameters, such as the ratio of electric to magnetic perturbations (Chaston et al 2008;Chaston et al 2009), magnetic compressibility (Podesta & TenBarge 2012), magnetic helicity (Howes et al 2010;Podesta et al 2011;He et al 2012), or the profile of wave dispersion (Sahraoui et al 2009;Sahraoui et al 2010;Roberts et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Properties of Short-Wavelength Oblique Alfvén and Slow Waves

Zhao

Voitenko

et al. 2014

ApJ

View full text Add to dashboard Cite

Linear properties of kinetic Alfvén waves (KAWs) and kinetic slow waves (KSWs) are studied in the framework of two-fluid magnetohydrodynamics. We obtain the wave dispersion relations that are valid in a wide range of the wave frequency ω and plasma-to-magnetic pressure ratio β. The KAW frequency can reach and exceed the ion cyclotron frequency at ion kinetic scales, whereas the KSW frequency remains sub-cyclotron. At β ∼ 1, the plasma and magnetic pressure perturbations of both modes are in anti-phase, so that there is nearly no total pressure perturbations. However, these modes exhibit also several opposite properties. At high β, the electric polarization ratios of KAWs and KSWs are opposite at the ion gyroradius scale, where KAWs are polarized in sense of electron gyration (right-hand polarized) and KSWs are left-hand polarized. The magnetic helicity σ ∼ 1 for KAWs and σ ∼ −1 for KSWs, and the ion Alfvén ratio R Ai ≪ 1 for KAWs and R Ai ≫ 1 for KSWs. We also found transition wavenumbers where KAWs change their polarization from leftto right-hand. These new properties can be used to discriminate KAWs and KSWs when interpreting kinetic-scale electromagnetic fluctuations observed in various solar-terrestrial plasmas. This concerns, in particular, identification of modes responsible for kinetic-scale pressure-balanced fluctuations and turbulence in the solar wind.

show abstract