High-Resolution Observations of the Shock Wave Behavior for Sunspot Oscillations With the Interface Region Imaging Spectrograph

Tian, Hui; DeLuca, E. E.; Reeves, Katharine K.; McKillop, S.; Pontieu, Bart De; Martínez-Sykora, Juan; Carlsson, Mats; Hansteen, V. H.; Kleint, Lucia; Cheung, Mark C. M.; Golub, L.; Saar, Steven H.; Testa, Paola; Weber, Mark; Lemen, J. R.; Title, A. M.; Boerner, P.; Hurlburt, N. E.; Tarbell, T. D.; Wüelser, Jean-Pierre; Kankelborg, C. C.; Jaeggli, Sarah A.; McIntosh, Scott W.

doi:10.1088/0004-637x/786/2/137

Cited by 120 publications

(125 citation statements)

References 54 publications

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“…Figure 10, extracted from Brynildsen et al (1999a), shows that the intensity-velocity time lags are very small, characteristic for the vertical wave propagation. With a better temporal resolution, Tian et al (2014) find that the intensity enhancement of the Mg ii 2796Å line formed in the high chromosphere occurs slightly before the maximum blueshift is reached. A similar behavior was also found for the Ca ii H and K lines by Rouppe van der Voort et al (2003).…”

Section: Oscillations In the Transition Region And Coronamentioning

confidence: 92%

“…From these parameters, some authors have suggested that the three-minute chromospheric oscillations above sunspot umbrae are standing acoustic waves , while others found them to be propagating waves able to reach the upper layers of the solar atmosphere Banerjee et al, 2002;O'Shea et al, 2002;Brynildsen et al, 2003Brynildsen et al, , 2004Kobanov and Makarchik, 2004). The typical sawtooth pattern of propagating shock wave fronts has been made patent in many observations using different chromospheric and transition region lines (see, e.g., Rouppe van der Voort et al, 2003;Centeno et al, 2006;Tian et al, 2014). Examples of such profiles are given in Figures 3 and 5 as derived from the observations in He i and Ca ii H lines in the above mentioned works.…”

Section: Propagation From the Photosphere To The Chromospherementioning

confidence: 99%

“…The 3-min disturbances have progressively larger time lags for spectral lines with higher formation heights in the transition region and corona. This leads to a natural interpretation in terms of upward propagating waves (Brynildsen et al, 1999a(Brynildsen et al, ,b, 2000Tian et al, 2014). The first interpretation of the TRACE observations of propagating slow waves in the EUV band was provided by Nakariakov et al (2000).…”

Section: Oscillations In the Transition Region And Coronamentioning

confidence: 99%

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Oscillations and Waves in Sunspots

Khomenko

Collados

2015

Living Rev. Sol. Phys.

152

118

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A magnetic field modifies the properties of waves in a complex way. Significant advances have been made recently in our understanding of the physics of sunspot waves with the help of high-resolution observations, analytical theories, as well as numerical simulations. We review the current ideas in the field, providing the most coherent picture of sunspot oscillations as by present understanding. Article RevisionsLiving Reviews supports two ways of keeping its articles up-to-date:Fast-track revision. A fast-track revision provides the author with the opportunity to add short notices of current research results, trends and developments, or important publications to the article. A fast-track revision is refereed by the responsible subject editor. If an article has undergone a fast-track revision, a summary of changes will be listed here.Major update. A major update will include substantial changes and additions and is subject to full external refereeing. It is published with a new publication number.For detailed documentation of an article's evolution, please refer to the history document of the article's online version at http://dx

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Section: Oscillations In the Transition Region And Coronamentioning

confidence: 92%

Section: Propagation From the Photosphere To The Chromospherementioning

confidence: 99%

Section: Oscillations In the Transition Region And Coronamentioning

confidence: 99%

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Oscillations and Waves in Sunspots

Khomenko

Collados

2015

Living Rev. Sol. Phys.

152

118

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“…The EUV observations from the Atmospheric Imaging Assembly (AIA; Lemen et al 2012) onboard the Solar Dynamics Observatory (SDO; Pesnell et al 2012) were used to compare with the IRIS data. Cross-correlation between the AIA 1600 Å image and the IRIS SJI 1400 Å image was used for the coalignment (Tian et al 2014b). The full-disk line-ofsight magnetograms from the Helioseismic and Magnetic Imager (HMI; Scherrer et al 2012) were also applied to analyze the magnetic structures at the BPs.…”

Section: Observations and Data Analysismentioning

confidence: 99%

Subarcsecond bright points and quasi-periodic upflows below a quiescent filament observed by IRIS

Zhang

2016

A&A

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Context. The new Interface Region Imaging Spectrograph (IRIS) mission provides high-resolution observations of UV spectra and slit-jaw images (SJIs). These data have become available for investigating the dynamic features in the transition region (TR) below the on-disk filaments. Aims. The driver of "counter-streaming" flows along the filament spine is still unknown yet. The magnetic structures and the upflows at the footpoints of the filaments and their relations with the filament mainbody have not been well understood. We study the dynamic evolution at the footpoints of filaments in order to find some clues for solving these questions. Methods. Using UV spectra and SJIs from the IRIS, along with coronal images and magnetograms from the Solar Dynamics Observatory (SDO), we present the new features in a quiescent filament channel: subarcsecond bright points (BPs) and quasi-periodic upflows.Results. The BPs in the TR have a spatial scale of about 350−580 km and lifetimes of more than several tens of minutes. They are located at stronger magnetic structures in the filament channel with a magnetic flux of about 10 17 −10 18 Mx. Quasi-periodic brightenings and upflows are observed in the BPs, and the period is about 4−5 min. The BP and the associated jet-like upflow comprise a "tadpole-shaped" structure. The upflows move along bright filament threads, and their directions are almost parallel to the spine of the filament. The upflows initiated from the BPs with opposite polarity magnetic fields have opposite directions. The velocity of the upflows in the plane of sky is about 5−50 km s −1 . The emission line of Si IV 1402.77 Å at the locations of upflows exhibits obvious blueshifts of about 5−30 km s −1 , and the line profile is broadened with the width of more than 20 km s −1 . Conclusions. The BPs seem to be the bases of filament threads, and the upflows are able to convey mass for the dynamic balance of the filament. The "counter-streaming" flows in previous observations may be caused by the propagation of bi-directional upflows initiated from opposite polarity magnetic fields. We suggest that quasi-periodic brightenings of BPs and quasi-periodic upflows result from small-scale oscillatory magnetic reconnections, which are modulated by solar p-mode waves.

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“…Figure 4 shows the effect of de-spiking. In addition, small spectral shifts caused by thermal drifts and the spacecraft orbital velocity were corrected with the routine iris_orbitvar_corr_12.pro (McIntosh et al 2013;Tian et al 2014;Cheng et al 2015) in the SSW package.…”

Section: Iris Observationsmentioning

confidence: 99%

Observations of solar flares with IRIS and SDO

Innes

Ning

2016

A&A

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Flare kernels brighten simultaneously in all Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) channels making it difficult to determine their temperature structure. The Interface Region Imaging Spectrograph (IRIS) is able to spectrally resolve Fe xxi emission from cold chromospheric brightenings, so it can be used to infer the amount of Fe xxi emission in the 131 Å AIA channel. We use observations of two small solar flares seen by IRIS and SDO to compare the emission measures (EMs) deduced from the IRIS Fe xxi line and the AIA 131 Å channel to determine the fraction of Fe xxi emission in flare kernels in the 131 Å channel of AIA. Cotemporal and cospatial pseudo-raster AIA images are compared with the IRIS results. We use multi-Gaussian line fitting to separate the blending chromospheric emission so as to derive Fe xxi intensities and Doppler shifts in IRIS spectra. We define loop and kernel regions based on the brightness of the 131 Å and 1600 Å intensities. In the loop regions the Fe xxi EMs are typically 80% of the 131 Å values, and range from 67% to 92%. Much of the scatter is due to small misalignments, but the largest site with low Fe xxi contributions was probably affected by a recent injection of cool plasma into the loop. In flare kernels the contribution of Fe xxi increases from less than 10% at the low-intensity 131 Å sites to 40−80% in the brighter kernels. Here the Fe xxi is superimposed on bright chromospheric emission and the Fe xxi line shows blueshifts, sometimes extending up to the edge of the spectral window, 200 km s −1 . The AIA 131 Å emission in flare loops is due to Fe xxi emission with a 10−20% contribution from continuum, Fe xxiii, and cooler background plasma emission. In bright flare kernels up to 52% of the 131 Å is from cooler plasma. The wide range seen in the kernels is caused by significant structure in the kernels, which is seen as sharp gradients in Fe xxi EM at sites of molecular and transition region emission.

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High-Resolution Observations of the Shock Wave Behavior for Sunspot Oscillations With the Interface Region Imaging Spectrograph

Cited by 120 publications

References 54 publications

Oscillations and Waves in Sunspots

Oscillations and Waves in Sunspots

Subarcsecond bright points and quasi-periodic upflows below a quiescent filament observed by IRIS

Observations of solar flares with IRIS and SDO

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