Damping of slow surface kink modes in solar photospheric waveguides modeled by one-dimensional inhomogeneities

Abstract

Given the recent interest in magnetohydrodynamic (MHD) waves in pores and sunspot umbrae, we examine the damping of slow surface kink modes (SSKMs) by modeling solar photospheric waveguides with a cylindrical inhomogeneity comprising a uniform interior, a uniform exterior, and a continuous transition layer (TL) in between. Performing an eigen-mode analysis in linear, resistive, gravity-free MHD, our approach is idealized in that, among other things, our equilibrium is structured only in the radial direction. We can nonetheless address two damping mechanisms simultaneously, one being the Ohmic resistivity, and the other being the resonant absorption of SSKMs in the cusp and Alfv$\acute{\mathrm{e}}$n continua. We find that the relative importance of the two mechanisms depends sensitively on the magnetic Reynolds number ($R_{\mathrm{m}}$). Resonant absorption is the sole damping mechanism for realistically large values of $R_{\mathrm{m}}$, and the cusp resonance in general dominates the Alfv$\acute{\mathrm{e}}$n one unless the axial wavenumbers are at the lower end of the observationally relevant range. We also find that the thin-boundary approximation holds only when the TL-width-to-radius ratios are much smaller than nominally expected. The Ohmic resistivity is far more important for realistically small $R_{\mathrm{m}}$. Even in this case, SSKMs are only marginally damped, with damping-time-to-period-ratios reaching $\sim 10$ in the parameter range we examine.

35 pages, 10 figures, accepted for publication in ApJ

References in corpus (14)

• A Contemporary View of Coronal Heating
• Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results
• Global maps of the magnetic field in the solar corona
• Heating mechanisms in the low solar atmosphere through magnetic reconnection in current sheets
• Magnetohydrodynamic kink waves in nonuniform solar flux tubes: phase mixing and energy cascade to small scales
• Damping of filament thread oscillations: effect of the slow continuum
• Transverse Oscillations in Slender Ca II H Fibrils Observed with Sunrise/SuFI
• An Inside Look at Sunspot Oscillations with Higher Azimuthal Wavenumbers
• Magnetohydrodynamic Seismology of Quiet Solar Active Regions
• Magnetoacoustic Wave Energy Dissipation in the Atmosphere of Solar Pores
• The Physical Nature of Spiral Wave Patterns in Sunspots
• Kink Oscillations in Solar Coronal Loops with Elliptical Cross-Sections. I. the linear regime
• Resonant absorption of surface sausage and surface kink modes under photospheric conditions
• Phase Mixing of Kink MHD Waves in the Solar Corona: Viscous Dissipation and Heating

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• Quasimodes in the cusp continuum in nonuniform magnetic flux tubes
• Oblique Quasi-Kink Modes in Solar Coronal Slabs Embedded in an Asymmetric Magnetic Environment: Resonant Damping, Phase and Group Diagrams
• Stability of solar atmospheric structures harboring standing slow waves: An analytical model in a compressible plasma