Oscillations in solar jets observed with the SOT of Hinode: viscous effects during reconnection

Tavabi, E.; Koutchmy, S.

doi:10.1007/s10509-014-1875-1

Cited by 5 publications

(4 citation statements)

References 43 publications

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“…It can be seen that increase and reduction of powers are not regular at four separate heights for the three datasets, more like randomly behavior. It is noted that the results randomly are obtained for selective time-slices, and the results are consistent which obtained by Hanstoen et al (2000) and Tavabi (2014). Gupta et al 2013 studied quiet Sun oscillations using the Fourier power and phase difference analysis from the intensity time series.…”

Section: Summery and Conclusionsupporting

confidence: 89%

“…We applied mad-max operator to clear the images as shown in figures 1b, 1d and 1f. The operator reduces considerably background noise (Koutchmy & koutchmy 1989;November & koutchmy 1996;Tavabi et al 2013 andTavabi 2014). This non-linear spatial filtering clearly shows relatively rather bright radial threads in the chromosphere as fine as the resolution limit of about 120 km.…”

Section: Discussionmentioning

confidence: 92%

“…In addition, they concentrated the analysis on the taller Ca II spicules more relevant for coronal heights and easier to measure. Tavabi (2014) studied off-limb and on-disk spicules to find a counterpart of the limb spicule on the disk and found a definite signature with strong power in the 3 min (5.5 mHz) and 5 min (3.5 mHz), a full range of oscillations and the high frequency intensity fluctuation (greater than 10 mHz or less than 100 s) corresponding to the occurrence of the so-called type II spicules.…”

Section: Introductionmentioning

confidence: 99%

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Spicules Intensity Oscillations in SOT/HINODE Observations

et al. 2015

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Aims. We study the coherency of solar spicules intensity oscillations with increasing height above the solar limb in quiet Sun, active Sun and active region using observations from HINODE/SOT. Existence of coherency up to transition region strengthens the theory of the coronal heating and solar wind through energy transport and photospheric oscillations. Methods. Using time sequences from the HINODE/SOT in Ca II H line, we investigate oscillations found in intensity profiles at different heights above the solar limb. We use the Fourier and wavelet analysis to measure dominant frequency peaks of intensity at the heights, and phase difference between oscillations at two certain heights, to find evidence for the coherency of the oscillations. Finally, we can calculate the energy and the mass transported by spicules providing energy equilibrium, according to density values of spicules at different heights. To extend this work, we can also consider coherent oscillations at different latitudes and suggest to study of oscillations which may be obtained from observations of other satellites.Comment: 17 pages and 17 figs., Accepted in JOA

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Section: Summery and Conclusionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Spicules Intensity Oscillations in SOT/HINODE Observations

et al. 2015

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“…Such interactions and the complex structuring of the magnetic fields may also generate the magnetic reconnection at small spatial scales, which may cause localized heating and the formation of jet-like plasma ejecta in the lower solar atmosphere (e.g., [2,7,11,12,17,[24][25][26][27][28][29][30][31][32][33] and references therein). In conclusion, there is a non-exhaustive list of studies where the evolution, triggering, kinematics, and energetics of the various solar jets are mentioned, highlighting the significance of these studies (e.g., [34][35][36][37][38] and references therein).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations of the Decaying Transverse Oscillations in the Cool Jet

Srivastava

Singh

2023

Physics

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In the present paper, we describe a 2.5D (two-and-a-half-dimensional) magnetohydrodynamic (MHD) simulation that provides a detailed picture of the evolution of cool jets triggered by initial vertical velocity perturbations in the solar chromosphere. We implement random multiple velocity, Vy, pulses of amplitude 20–50 km s−1 between 1 Mm and 1.5 Mm in the Sun’s atmosphere below its transition region (TR). These pulses also consist of different switch-off periods between 50 s and 300 s. The applied vertical velocity pulses create a series of magnetoacoustic shocks steepening above the TR. These shocks interact with each other in the inner corona, leading to complex localized velocity fields. The upward propagation of such perturbations creates low-pressure regions behind them, which propel a variety of cool jets and plasma flows in the localized corona. The localized complex velocity fields generate transverse oscillations in some of these jets during their evolution. We study the transverse oscillations of a representative cool jet J1, which moves up to the height of 6.2 Mm above the TR from its origin point. During its evolution, the plasma flows make the spine of jet J1 radially inhomogeneous, which is visible in the density and Alfvén speed smoothly varying across the jet. The highly dense J1, which is triggered along the significantly curved magnetic field lines, supports the propagating transverse wave of period of approximately 195 s with a phase speed of about 125 km s−1. In the distance–time map of density, it is manifested as a transverse kink wave. However, the careful investigation of the distance–time maps of the x- and z-components of velocity reveals that these transverse waves are actually of mixed Alfvénic modes. The transverse wave shows evidence of damping in the jet. We conclude that the cross-field structuring of the density and characteristic Alfvén speed within J1 causes the onset of the resonant conversion and leakage of the wave energy outward to dissipate these transverse oscillations via resonant absorption. The wave energy flux is estimated as approximately of 1.0 × 106 ergs cm−2 s−1. This energy, if it dissipates through the resonant absorption into the corona where the jet is propagated, is sufficient energy for the localized coronal heating.

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Improved SOT (Hinode mission) high resolution solar imaging observations

Goodarzi

Koutchmy

Adjabshirizadeh

2015

Astrophys Space Sci

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We consider the best today available observations of the Sun free of turbulent Earth atmospheric effects, taken with the Solar Optical Telescope (SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the observed stray light are analyzed in order to improve the resolution. The Point Spread Function (PSF) corresponding to the blue continuum Broadband Filter Imager (BFI) near 450 nm is deduced by analyzing i/ the limb of the Sun and ii/ images taken during the transit of the planet Venus in 2012. A combination of Gaussian and Lorentzian functions is selected to construct a PSF in order to remove both smearing due to the instrumental diffraction effects (PSF core) and the large-angle stray light due to the spiders and central obscuration (wings of the PSF) that are responsible for the parasitic stray light. A Max-likelihood deconvolution procedure based on an optimum number of iterations is discussed. It is applied to several solar field images, including the granulation near the limb. The normal non-magnetic granulation is compared to the abnormal granulation which we call magnetic. A new feature appearing for the first time at the extreme-limb of the disk (the last 100 km) is discussed in the context of the definition of the solar edge and of the solar diameter. A single sunspot is considered in order to illustrate how effectively the restoration works on the sunspot core. A set of 125 consecutive deconvolved images is assembled in a 45 min long movie illustrating the complexity of the dynamical behavior inside and around the sunspot.

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Oscillations in solar jets observed with the SOT of Hinode: viscous effects during reconnection

Cited by 5 publications

References 43 publications

Spicules Intensity Oscillations in SOT/HINODE Observations

Spicules Intensity Oscillations in SOT/HINODE Observations

Numerical Simulations of the Decaying Transverse Oscillations in the Cool Jet

Improved SOT (Hinode mission) high resolution solar imaging observations

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