Hi-C and AIA observations of transverse magnetohydrodynamic waves in active regions

Morton, R. J.; McLaughlin, James

doi:10.1051/0004-6361/201321465

Cited by 56 publications

(58 citation statements)

References 17 publications

(25 reference statements)

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“…As a starting point, we state that several recent observations of loops/spicules in groups have an apparent interstructure distance of about one tube width, see, e.g., Figure 2 (top, middle panel) and Figure 4 in Morton & McLaughlin (2013) for coronal loops and Figure 2B (bottom right corner) in De Pontieu et al (2007) for spicules. However, an intertube distance of about one tube diameter can be the result of several three-dimensional (3D) configurations (that have been integrated over the line of sight).…”

Section: Considerations On Fmentioning

confidence: 61%

“…Likewise, the energy flux estimates in transverse waves in coronal loops of 100 W m −2 reported by McIntosh et al (2011) (who calculated the energy flux using a "wave filling factor" of 100%) would be reduced to 10-20 W m −2 , using a density filling factor of 10% for their observed loop bundle. In this recalculation, we have not taken into account the claim of Morton & McLaughlin (2013) that the velocity amplitudes measured with Hi-C are smaller than the one used in McIntosh et al (2011). In the recent paper by Thurgood et al (2014), the reported energy flux of transverse waves in polar plumes of 9-24 W m −2 would be lowered to 0.9-4.8 W m −2 with our formula, again, using a density filling factor of 10%.…”

Section: Discussionmentioning

confidence: 92%

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Energy Propagation by Transverse Waves in Multiple Flux Tube Systems Using Filling Factors

Doorsselaere

Gijsen

Andries

et al. 2014

ApJ

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In the last few years, it has been found that transverse waves are present at all times in coronal loops or spicules. Their energy has been estimated with an expression derived for bulk Alfvén waves in homogeneous media, with correspondingly uniform wave energy density and flux. The kink mode, however, is localized in space with the energy density and flux dependent on the position in the cross-sectional plane. The more relevant quantities for the kink mode are the integrals of the energy density and flux over the cross-sectional plane. The present paper provides an approximation to the energy propagated by kink modes in an ensemble of flux tubes by means of combining the analysis of single flux tube kink oscillations with a filling factor for the tube cross-sectional area. This finally allows one to compare the expressions for energy flux of Alfvén waves with an ensemble of kink waves. We find that the correction factor for the energy in kink waves, compared to the bulk Alfvén waves, is between f and 2f , where f is the density filling factor of the ensemble of flux tubes.

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Section: Considerations On Fmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 92%

Energy Propagation by Transverse Waves in Multiple Flux Tube Systems Using Filling Factors

Doorsselaere

Gijsen

Andries

et al. 2014

ApJ

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“…∼0.435 Mm) ranging in values around 0.3-0.6 Mm, and some values lower than 0.2 Mm. The reason for the sub-resolution estimation of the oscillation amplitude is the Gaussian fitting method, as pointed out also in Morton & McLaughlin (2013) using AIA and the High Resolution Coronal Imager (HI-C) data. …”

Section: åmentioning

confidence: 99%

Dynamics of a multi-thermal loop in the solar corona

Nisticò

Anfinogentov

Nakariakov

2014

A&A

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Context. We present an observation of a long-living multi-thermal coronal loop, visible in different extreme ultra-violet wavebands of SDO/AIA in a quiet-Sun region close to the western solar limb. Aims. Analysis of persistent kink displacements of the loop seen in different bandpasses that correspond to different temperatures of the plasma allows sub-resolution structuring of the loop to be revealed. Methods. A vertically oriented slit is taken at the loop top, and time-distance maps are made from it. Loop displacements in timedistance maps are automatically tracked with the Gaussian fitting technique and fitted with a sinusoidal function that is "guessed". Wavelet transforms are further used in order to quantify the periodicity variation in time of the kink oscillations. Results. The loop strands are found to oscillate with the periods ranging between 3 and 15 min. The oscillations are observed in intermittent regime with temporal changes in the period and amplitude. The oscillations are different at three analysed wavelengths.Conclusions. This finding suggests that the loop-like threads seen at different wavelengths are not co-spatial, hence that the loop consists of several multi-thermal strands. The detected irregularity of the oscillations can be associated with a stochastic driver acting at the footpoints of the loop.

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“…Their presence over extended regions of the solar corona (Tomczyk et al 2007) may have implications on the role of waves in coronal heating. Observations with instruments such as AIA/SDO, CoMP, and Hi-C by e.g., Morton & McLaughlin (2013) and Threlfall et al (2013) have allowed us to analyse transverse oscillations with unprecedented detail.…”

Section: Introductionmentioning

confidence: 99%

Determination of the cross-field density structuring in coronal waveguides using the damping of transverse waves

Arregui

Ramos

2014

A&A

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Context. Time and spatial damping of transverse magnetohydrodynamic (MHD) kink oscillations is a source of information on the cross-field variation of the plasma density in coronal waveguides. Aims. We show that a probabilistic approach to the problem of determining the density structuring from the observed damping of transverse oscillations enables us to obtain information on the two parameters that characterise the cross-field density profile. Methods. The inference is performed by computing the marginal posterior distributions for density contrast and transverse inhomogeneity length-scale using Bayesian analysis and damping ratios for transverse oscillations under the assumption that damping is produced by resonant absorption. Results. The obtained distributions show that, for damping times of a few oscillatory periods, low density contrasts and short inhomogeneity length scales are more plausible in explaining observations. Conclusions. This means that valuable information on the cross-field density profile can be obtained even if the inversion problem, with two unknowns and one observable, is a mathematically ill-posed problem.

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Hi-C and AIA observations of transverse magnetohydrodynamic waves in active regions

Cited by 56 publications

References 17 publications

Energy Propagation by Transverse Waves in Multiple Flux Tube Systems Using Filling Factors

Energy Propagation by Transverse Waves in Multiple Flux Tube Systems Using Filling Factors

Dynamics of a multi-thermal loop in the solar corona

Determination of the cross-field density structuring in coronal waveguides using the damping of transverse waves

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