Waves propagation in network and inter-network bright points channels between the chromosphere and transition regions with IRIS observations

Zeighami, S.; Tavabi, E.; Amirkhanlou, Elnaz

doi:10.1007/s12036-020-09633-y

Cited by 5 publications

(4 citation statements)

References 27 publications

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“…As Figure 9 shows, there is a correlation between two signals at certain times. We calculated the phase velocity of the two signals using a technique based on cross-correlation (Zeighami, Tavabi, and Amirkhanlou, 2020). In this method, the time lag between the two signals is…”

Section: Discussionmentioning

confidence: 99%

“…IRIS spacecraft contained a combination of telescope and spectrograph (De Pontieu et al, 2014b). IRIS obtains bservations of the solar transition region with a high spatial and spectral resolution to investigate the physical processes of fine structures (Chen et al, 2019, Tavabi and Koutchmy, 2019, Zeighami, Tavabi, and Amirkhanlou, 2020, Bose et al, 2021a. The spectral dispersion in the far and near-ltraviolet are about 0.025 Å and 0.053 Å, respectively.…”

Section: Observationsmentioning

confidence: 99%

“…In the image processing method, displacements and intensity changes in images are measured (Tavabi et al, 2015a). In the second method, periodic patterns in Doppler shifts are examined by spectrometers Golub, 2015, Tavabi, 2018;Koutchmy, 2019, andAmirkhanlou, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of Explosive Events Observed by the Interface Region Imaging Spectrograph

2022

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In this research, we investigate Explosive Events (EEs) in the off-limb solar atmosphere, with simultaneous observations from the Si IV, Mg II k, and slit-jaw images (SJI) of the Interface Region Imaging Spectrograph (IRIS), on 17 August 2014, and 19 February. IRIS data can be investigated to observe the motion of matter, fluctuations, energy absorption, and heat transition of the solar atmosphere. Mechanisms responsible for solar large-scale structures, such as flares and coronal mass ejections, might originate from these small-scale energetic events. Therefore, the study of these events can be helpful for understanding mechanisms in mass and energy transport from the chromosphere toward the transition region and corona. We obtain intensity profiles from spectra in two altitudes, i.e., at the solar limb and 5 arcsec distance from solar limb, and then analyze the EE fluctuations at these two altitudes along the slit. We find that some spectral line profiles show enhancements in blue and red wings indicating upward and downward flows, and some profiles have opposite EEs in both wings. The amplitude of the Doppler velocity in the two data sets of different altitudes was approximated to be about 50 km s −1 . We calculated the phase velocity of the oscillations using a technique based on cross-correlation. The phase velocity is obtained as about 220 km s −1 . According to the periodic red and blue enhancements in EEs, we suggest that the fluctuations in the EEs with one side enhancement indicate a swaying motions of spicules about their axes, and those EEs observed in both wings indicate a rotational motions of spicules. The swaying and rotational motions are indicative of kink and torsional waves, respectively.

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Section: Discussionmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

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Dynamics of Explosive Events Observed by the Interface Region Imaging Spectrograph

2022

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“…Zeighami et al (2020) studied the Doppler velocity above chromospheric network and internetwork points and obtained values of −21 to +21 for internetwork points and −20 to 30 km s −1 for network points Zhang et al (2021). reported the Doppler velocity value of a flare-related coronal jet to be about −120 to 170 km s −1 .…”

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confidence: 99%

A New Approach to Kinetic Energy Flux at the Different Frequencies above the IRIS Bright Points*

Rayhane

Tavabi

2022

ApJ

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Various bright structures abound in the chromosphere playing an essential role in the dynamics and evolution therein. Tentatively identifying the wave characteristics in the outer solar atmosphere helps to understand this layer better. One of the most significant aspects of these characteristics is the wave phase speed (PS), which is a dominant contribution to solar coronal heating and energy distribution in the Sun’s atmosphere layers. To obtain energy flux (EF), it is necessary to calculate the filling factor (FF) and the PS. In this study, the FF was determined by tracking the size and intensity of the IRIS bright points (BPs). To estimate an accurate PS and EF, it is necessary to know the chromosphere and transition region (TR) thickness and the phase difference between the two desired levels. Chromosphere and TR thickness cannot be measured directly on the disk; this study is performed using spectral data and calibrated based on Doppler velocities. As a result, the PSs in active regions (ARs) and coronal holes (CHs), as well as the IRIS BPs, have been calculated using the cross-power wavelet transform of Doppler velocities. Consequently, about the CH, the PS mean values are from 40 to 180 km s−1 at the network and from 30 to 140 km s−1 at the internetwork; and about the AR, they are from 80 to 540 km s−1 at the network and 70 to 220 km s−1 at the internetwork. Finally, the EF for the IRIS BPs has been calculated in three different frequencies. The results indicate that the network BPs have an influential role in heating the higher layers, while in the internetwork BPs most of the energy returns to the lower layers.

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Waves in the lower solar atmosphere: the dawn of next-generation solar telescopes

Jess

Jafarzadeh

Keys

et al. 2023

Living Rev Sol Phys

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Waves and oscillations have been observed in the Sun’s atmosphere for over half a century. While such phenomena have readily been observed across the entire electromagnetic spectrum, spanning radio to gamma-ray sources, the underlying role of waves in the supply of energy to the outermost extremities of the Sun’s corona has yet to be uncovered. Of particular interest is the lower solar atmosphere, including the photosphere and chromosphere, since these regions harbor the footpoints of powerful magnetic flux bundles that are able to guide oscillatory motion upwards from the solar surface. As a result, many of the current- and next-generation ground-based and space-borne observing facilities are focusing their attention on these tenuous layers of the lower solar atmosphere in an attempt to study, at the highest spatial and temporal scales possible, the mechanisms responsible for the generation, propagation, and ultimate dissipation of energetic wave phenomena. Here, we present a two-fold review that is designed to overview both the wave analyses techniques the solar physics community currently have at their disposal, as well as highlight scientific advancements made over the last decade. Importantly, while many ground-breaking studies will address and answer key problems in solar physics, the cutting-edge nature of their investigations will naturally pose yet more outstanding observational and/or theoretical questions that require subsequent follow-up work. This is not only to be expected, but should be embraced as a reminder of the era of rapid discovery we currently find ourselves in. We will highlight these open questions and suggest ways in which the solar physics community can address these in the years and decades to come.

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Waves propagation in network and inter-network bright points channels between the chromosphere and transition regions with IRIS observations

Cited by 5 publications

References 27 publications

Dynamics of Explosive Events Observed by the Interface Region Imaging Spectrograph

Dynamics of Explosive Events Observed by the Interface Region Imaging Spectrograph

A New Approach to Kinetic Energy Flux at the Different Frequencies above the IRIS Bright Points*

Waves in the lower solar atmosphere: the dawn of next-generation solar telescopes

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