Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Jess, D. B.; Verth, G.

doi:10.1002/9781119055006.ch26

Cited by 14 publications

(6 citation statements)

References 141 publications

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“…This should enable the magnetic features to be better probed, e.g., as done by Domínguez Cerdeña et al ( 2003) and Buehler et al (2015) using complementary approaches. Possible future applications of deconvolution include catching the detailed process of convective collapse coinciding with a downflow within the magnetic features (Parker 1978), as observed by Nagata et al (2008) and Requerey et al (2014), and described using MHD simulations by Danilovic et al (2010), or the magneto-acoustic waves generated intermittently in flux tubes (e.g., Stangalini et al 2014, Jess & Verth 2016, which are excited by the surrounding convective motions (Kato et al 2016).…”

Section: Discussionmentioning

confidence: 99%

The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode/SP Data

Oba

Riethmüller

Solanki

et al. 2017

ApJ

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Solar granules are bright patterns surrounded by dark channels called intergranular lanes in the solar photosphere and are a manifestation of overshooting convection. Observational studies generally find stronger upflows in granules and weaker downflows in intergranular lanes. This trend is, however, inconsistent with the results of numerical simulations in which downflows are stronger than upflows through the joint action of gravitational acceleration/deceleration and pressure gradients. One cause of this discrepancy is the image degradation caused by optical distortion and light diffraction and scattering that takes place in an imaging instrument. We apply a deconvolution technique to Hinode/SP data in an attempt to recover the original solar scene. Our results show a significant enhancement in both, the convective upflows and downflows, but particularly for the latter. After deconvolution, the up-and downflows reach maximum amplitudes of -3.0 km/s and +3.0 km/s at an average geometrical height of roughly 50 km, respectively. We found that the velocity distributions after deconvolution match those derived from numerical simulations. After deconvolution the net LOS velocity averaged over the whole FOV lies close to zero as expected in a rough sense from mass balance.

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Section: Discussionmentioning

confidence: 99%

The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode/SP Data

Oba

Riethmüller

Solanki

et al. 2017

ApJ

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“…The solar atmosphere consists of a large variety of magnetic structures capable of maintaining different types of magnetohydrodynamic (MHD) waves [1][2][3][4]. While these could be in part responsible for the plasma heating in the upper solar atmosphere (by means of energy deposition in those layers), the exact physical mechanisms of which still remain unclear (see [5,6] and references therein for a wider picture).…”

Section: Introductionmentioning

confidence: 99%

High-frequency oscillations in small chromospheric bright features observed with Atacama Large Millimetre/Submillimetre Array

Gómez

Jafarzadeh

Wedemeyer

et al. 2020

Phil. Trans. R. Soc. A.

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We report detection of oscillations in brightness temperature, size and horizontal velocity of three small bright features in the chromosphere of a plage/enhanced-network region. The observations, which were taken with high temporal resolution (i.e. 2 s cadence) with the Atacama large millimetre/ submillimetre array (ALMA) in Band 3 (centred at 3 mm; 100 GHz), exhibit three small-scale features with oscillatory behaviour with different, but overlapping, distributions of period on the order of, on average, 90 ± 22 s, 110 ± 12 s and 66 ± 23 s, respectively. We find anti-correlations between perturbations in brightness, temperature and size of the three features, which suggest the presence of fast sausage-mode waves in these small structures. In addition, the detection of transverse oscillations (although with a larger uncertainty) may also suggest the presence of Alfvénic oscillations which are likely representative of kink waves. This work demonstrates the diagnostic potential of high-cadence observations with ALMA for detecting high-frequency magnetohydrodynamic waves in the solar chromosphere. Such waves can potentially channel a vast amount of energy into the outer atmosphere of the Sun. This article is part of the Theo Murphy meeting issue ‘High-resolution wave dynamics in the lower solar atmosphere’.

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“…The magnitude of such non‐thermal line broadening will be dependent on both the velocity amplitude of the Alfvén wave, as well as the inclination angle of the waveguide with respect to the observer's line‐of‐sight (i.e., the cos term will modulate the degree of Doppler‐induced broadening visible to the observer). Furthermore, turbulence and/or bulk flows embedded within the flux tube may also mask the presence of FWHM oscillations caused by Alfvén waves (Jess & Verth, 2016). As a result, a combination of high spatial resolution observations and high precision spectroscopy is required to unequivocally detect the presence of Alfvén waves manifesting in the lower solar atmosphere.…”

Section: Waves In Structured Flux Tubes In the Chromospherementioning

confidence: 99%

Chromospheric Heating by Magnetohydrodynamic Waves and Instabilities

et al. 2021

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The importance of the chromosphere in the mass and energy transport within the solar atmosphere is now widely recognised. This review discusses the physics of magnetohydrodynamic (MHD) waves and instabilities in large-scale chromospheric structures as well as in magnetic flux tubes. We highlight a number of key observational aspects that have helped our understanding of the role of the solar chromosphere in various dynamic processes and wave phenomena, and the heating scenario of the solar chromosphere is also discussed. The review focuses on the physics of waves and invokes the basics of plasma instabilities in the context of this important layer of the solar atmosphere. Potential implications, future trends and outstanding questions are also delineated.

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Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Cited by 14 publications

References 141 publications

The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode/SP Data

The Small-scale Structure of Photospheric Convection Retrieved by a Deconvolution Technique Applied to Hinode/SP Data

High-frequency oscillations in small chromospheric bright features observed with Atacama Large Millimetre/Submillimetre Array

Chromospheric Heating by Magnetohydrodynamic Waves and Instabilities

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