The dynamics of 3-minute wavefronts and their relation to sunspot magnetic fields
arXiv:2007.09369 · doi:10.1098/rsta.2020.0180
Abstract
We present a study of wave processes occurring in solar active region NOAA 11131 on 2010 December 10, captured by the Solar Dynamics Observatory in the 1600A, 304A, and 171A channels. For spectral analysis we employed pixelised wavelet filtering together with a developed digital technique based on empirical mode decomposition. We studied the 3-minute wave dynamics to obtain relationships with the magnetic structuring of the underlying sunspot. We found that during development of wave trains the motion path occurred along a preferential direction, and that the broadband wavefronts can be represented as a set of separate narrowband oscillation sources. These sources become visible as the waves pass through the umbral inhomogeneities caused by the differing magnetic field inclination angles. We found the spatial and frequency fragmentation of wavefronts, and deduced that the combination of narrowband spherical and linear parts of the wavefronts provide the observed spirality. Maps of the magnetic field inclination angles confirm this assumption. We detect the activation of umbral structures as the increasing of oscillations in the sources along the front ridge. Their temporal dynamics are associated with the occurrence of umbral flashes. Spatial localisation of the sources is stable over time and depends on the oscillation period. We propose that these sources are the result of wave paths along the loops extending outwards from the magnetic bundles of the umbra.
arXiv comment18 pages, 8 figures, accepted to publication in Royal Society Philosophical Transactions A
References in corpus (33)
- VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager
- Dynamic Fibrils are driven by Magnetoacoustic Shocks
- Nonlinear force-free modeling of the solar coronal magnetic field
- Magnetic Structure of Sunspots
- Alfvén Wave Dissipation in the Solar Chromosphere
- The Influence of the Magnetic Field on Running Penumbral Waves in the Solar Chromosphere
- Solar coronal magnetic fields derived using seismology techniques applied to omnipresent sunspot waves
- The Source of Three-minute Magneto-acoustic Oscillations in Coronal Fans
- Propagating slow magnetoacoustic waves in coronal loops observed by Hinode/EIS
- Three-minute oscillations above sunspot umbra observed with SDO/AIA and NoRH
- Wave Propagation and Jet Formation in the Chromosphere
- Multi-height observations of magnetoacoustic cut-off frequency in a sunspot atmosphere
- Opposite polarity field with convective downflow and its relation to magnetic spines in a sunspot penumbra
- Short dynamic fibrils in sunspot chromospheres
- Propagating Disturbances in Coronal Loops: A Detailed Analysis of Propagation Speeds
- An Inside Look at Sunspot Oscillations with Higher Azimuthal Wavenumbers
- Detection of sea-serpent field lines in sunspot penumbrae
- Frequency drifts of 3-min oscillations in microwave and EUV emission above sunspots
- The Magnetic Response of the Solar Atmosphere to Umbral Flashes
- Wave dynamics in a sunspot umbra
- High Resolution Observations of Chromospheric Jets in Sunspot Umbra
- Tracing the Chromospheric and Coronal Magnetic Field with AIA, IRIS, IBIS, and ROSA Data
- The Physical Nature of Spiral Wave Patterns in Sunspots
- Local sunspot oscillations and umbral dots
- Web-Based Data Processing System for Automated Detection of Oscillations with Applications to the Solar Atmosphere
- Stable Umbral Chromospheric Structures
- Spiral-shaped wavefronts in a sunspot umbra
- Observations of Running Penumbral Waves emerging in a Sunspot
- Properties of local oscillations in the lower sunspot atmosphere
- MHD waves in sunspots
- Fine wave dynamics in umbral flash sources
- Peculiarity of the oscillation stratification in sunspot penumbrae
- Oscillations in the Flaring Active Region NOAA 11272