Propagation of acoustic waves in the non‐isothermal solar atmosphere

Routh, Swati; Musielak, Z. E.

doi:10.1002/asna.201412128

Cited by 12 publications

(13 citation statements)

References 23 publications

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“…Similar results were obtained by more recent theoretical work (e.g, Fawzy & Musielak 2012;Routh & Musielak 2014) in which more realistic (Vernazza et al 1981) solar atmosphere models were adopted.…”

Section: Discussionsupporting

confidence: 88%

Vertical propagation of acoustic waves in the solar internetworkas observed by IRIS

Kayshap

Murawski

Srivastava

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We investigate the Interface Region Imaging Spectrograph (IRIS) observations of the quiet-Sun (QS) to understand the propagation of acoustic waves in transition region (TR) from photosphere. We selected a few IRIS spectral lines, which include the photospheric (Mn i 2801.25Å), chromospheric (Mg ii k 2796.35Å) and TR (C ii 1334.53Å), to investigate the acoustic wave propagation. The wavelet cross-spectrum reveals significant coherence (about 70% locations) between photosphere and chromosphere. Few minutes oscillations (i.e., period range from 1.6 to 4.0 minutes) successfully propagate into chromosphere from photosphere, which is confirmed by dominance of positive phase lags. However, in higher period regime (i.e., greater than ≈ 4.5 minutes), the downward propagation dominates is evident by negative phase lags. The broad spectrum of waves (i.e., 2.5-6.0 minutes) propagates freely upwards from chromosphere to TR. We find that only about 45% locations (out of 70%) show correlation between chromosphere and TR. Our results indicate that roots of 3 minutes oscillations observed within chromosphere/TR are located in photosphere. Observations also demonstrate that 5 minute oscillations propagate downward from chromosphere.However, some locations within QS also show successful propagation of 5 minute oscillations as revealed by positive phase lags, which might be the result of magnetic field. In addition, our results clearly show that a significant power, within period ranging from 2.5 to 6.0 minutes, of solar chromosphere is freely transmitted into TR triggering atmospheric oscillations. Theoretical implications of our observational results are discussed.

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Section: Discussionsupporting

confidence: 88%

Vertical propagation of acoustic waves in the solar internetworkas observed by IRIS

Kayshap

Murawski

Srivastava

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…It appears that this effect was previously noted in a numerical study of chromospheric oscillations (Kalkofen et al 1994). More general solutions incorporating the effects caused by a temperature gradient (Routh & Musielak 2014) or a nonuniform background magnetic field (Afanasyev & Nakariakov 2015) would be required to achieve a more accurate description of the waves in the transition region where the plasma beta decreases rapidly with height.…”

Section: Discussionmentioning

confidence: 99%

“…In the remainder of the paper, we develop an analytical description of nonlinear acoustic waves, which should apply to the observed three-minute oscillations, caused by slow magnetoacoustic waves propagating along the chromospheric magnetic field (O'Shea et al 2002). We focus on the propagation of finiteamplitude acoustic waves and neglect the effects caused by a temperature gradient (Routh & Musielak 2014) and a nonuniform background magnetic field (Afanasyev & Nakariakov 2015). Our approach is justified as long as the background temperature gradient and magnetic field are weak enough.…”

Section: Basic Equationsmentioning

confidence: 99%

“…(22), is small in comparison with the characteristic lengths of a more complete solution incorporating the temperature gradient and magnetic field effects. Analysis of the linearized equations suggest that those effects become significant in a low-beta plasma above the transition region separating the chromosphere and corona (Routh & Musielak 2014;Afanasyev & Nakariakov 2015).…”

Section: Basic Equationsmentioning

confidence: 99%

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Analytical description of nonlinear acoustic waves in the solar chromosphere

Litvinenko

Chae

2017

A&A

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Aims. Vertical propagation of acoustic waves of finite amplitude in an isothermal, gravitationally stratified atmosphere is considered. Methods. Methods of nonlinear acoustics are used to derive a dispersive solution, which is valid in a long-wavelength limit, and a non-dispersive solution, which is valid in a short-wavelength limit. The influence of the gravitational field on wave-front breaking and shock formation is described. The generation of a second harmonic at twice the driving wave frequency, previously detected in numerical simulations, is demonstrated analytically. Results. Application of the results to three-minute chromospheric oscillations, driven by velocity perturbations at the base of the solar atmosphere, is discussed. Numerical estimates suggest that the second harmonic signal should be detectable in an upper chromosphere by an instrument such as the Fast Imaging Solar Spectrograph installed at the 1.6-m New Solar Telescope of the Big Bear Observatory.

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“…Its physical situation is much more complex than our solution. First, the temperature gradient starts to have a significant effect in the upper atmosphere (Routh & Musielak 2014;Murawski et al 2016). Second, the analytical description of shock waves requires a special treatment of discontinuities such as making use of jump conditions in addition to the continuous solution we have obtained.…”

Section: Discussionmentioning

confidence: 99%

Nonlinear Effects in Three-minute Oscillations of the Solar Chromosphere. I. An Analytical Nonlinear Solution and Detection of the Second Harmonic

Chae

Litvinenko

2017

ApJ

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The vertical propagation of nonlinear acoustic waves in an isothermal atmosphere is considered. A new analytical solution that describes a finite-amplitude wave of an arbitrary wavelength is obtained. Although the short-and long-wavelength limits were previously considered separately, the new solution describes both limiting cases within a common framework and provides a straightforward way of interpolating between the two limits. Physical features of the nonlinear waves in the chromosphere are described, including the dispersive nature of lowfrequency waves, the steepening of the wave profile, and the influence of the gravitational field on wavefront breaking and shock formation. The analytical results suggest that observations of three-minute oscillations in the solar chromosphere may reveal the basic nonlinear effect of oscillations with combination frequencies, superposed on the normal oscillations of the system. Explicit expressions for a second-harmonic signal and the ratio of its amplitude to the fundamental harmonic amplitude are derived. Observational evidence of the second harmonic, obtained with the Fast Imaging Solar Spectrograph, installed at the 1.6 m New Solar Telescope of the Big Bear Observatory, is presented. The presented data are based on the time variations of velocity determined from the Na I D 2 and Hα lines.

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Propagation of acoustic waves in the non‐isothermal solar atmosphere

Cited by 12 publications

References 23 publications

Vertical propagation of acoustic waves in the solar internetworkas observed by IRIS

Vertical propagation of acoustic waves in the solar internetworkas observed by IRIS

Analytical description of nonlinear acoustic waves in the solar chromosphere

Nonlinear Effects in Three-minute Oscillations of the Solar Chromosphere. I. An Analytical Nonlinear Solution and Detection of the Second Harmonic

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