Revisiting the relation between nonthermal line widths and transverse MHD wave amplitudes
arXiv:2007.02836 · doi:10.3847/1538-4357/aba429
Abstract
Observations and 3D MHD simulations of the transverse MHD waves in the solar corona have established that true wave energies hide in the nonthermal line widths of the optically thin emission lines. This displays the need for a relation between the nonthermal line widths and transverse wave amplitudes for estimating the true wave energies. In the past decade, several studies have assumed that the root mean square (rms) wave amplitudes are larger than nonthermal line widths by a factor of . However, a few studies have ignored this factor while estimating rms wave amplitudes. Thus there appears to exist a discrepancy in this relation. In this study, we investigate the dependence of nonthermal line widths on wave amplitudes by constructing a simple mathematical model followed by 3D MHD simulations. We derive this relation for the linearly polarised, circularly polarised oscillations, and oscillations excited by multiple velocity drivers. We note a fairly good match between mathematical models and numerical simulations. We conclude that the rms wave amplitudes are never greater than the nonthermal line widths which raises questions about earlier studies claiming transverse waves carry enough energy to heat the solar corona.
17 pages and 5 figures. Accepted for the publication in The Astrophysical Journal. (Few typos are corrected in this version)
References in corpus (22)
- On Solving the Coronal Heating Problem
- Time-Distance Seismology of the Solar Corona with CoMP
- MPI-AMRVAC for Solar and Astrophysics
- A Contemporary View of Coronal Heating
- Persistent Doppler shift oscillations observed with HINODE/EIS in the solar corona: spectroscopic signatures of Alfvenic waves and recurring upflows
- Wave Heating of the Solar Atmosphere
- Quasi-periodic Propagating Signals in the Solar Corona: The Signature of Magnetoacoustic Waves or High-Velocity Upflows?
- Signatures of Alfven waves in the polar coronal holes as seen by EIS/Hinode
- The Spectroscopic Signature of Quasi-periodic Upflows in Active Region Timeseries
- Observation of High-speed Outflow on Plume-like Structures of the Quiet Sun and Coronal Holes with SDO/AIA
- Evidence of Wave Damping at Low Heights in a Polar Coronal Hole
- Estimating the "Dark" Energy Content of the Solar Corona
- Spectroscopic signature of Alfvén waves damping in a polar coronal hole up to 0.4 solar radii
- Generalized phase mixing: Turbulence-like behaviour from unidirectionally propagating MHD waves
- The Heating of Solar Coronal Loops by Alfven Wave Turbulence
- Evidence for Wave Heating of the Quiet Sun Corona
- Understanding uniturbulence: self-cascade of MHD waves in the presence of inhomogeneities
- Solar off-limb line widths: Alfven waves, ion-cyclotron waves, and preferential heating
- The Spectroscopic Footprint of the Fast Solar Wind
- Hinode EIS line widths in the quiet corona up to 1.5 Rsun
- Exploring the damping of Alfvén waves along a long off-limb coronal loop, up to 1.4 R
- Coronal Density and Temperature Profiles Calculated by Forward Modeling EUV Emission Observed by SDO/AIA
Cited by in corpus (11)
- MPI-AMRVAC 3.0: updates to an open-source simulation framework
- MHD Waves in open coronal structures
- Weak damping of propagating MHD kink waves in the quiescent corona
- High frequency decayless waves with significant energy in Solar Orbiter/EUI observations
- Propagating Kink Waves in an Open Coronal Magnetic Flux Tube with Gravitational Stratification: Magnetohydrodynamic Simulation and Forward Modelling
- Forward Modeling of Simulated Transverse Oscillations in Coronal Loops and the Influence of Background Emission
- Uniturbulence and Alfven wave solar model
- How transverse MHD wave-driven turbulence influences the density filling factor in the solar corona?
- Fe XII and Fe XIII Line Widths in the Polar Off-limb Solar Corona up to 1.5 Rsun
- Investigating coronal wave energy estimates using synthetic non-thermal line widths
- High-Frequency Magnetohydrodynamic Waves with Substantial Energy in the Solar Polar Corona