Doppler Shift Oscillations from a Hot Line Observed by IRIS

Li, D.; Ning, Zongjun; Yu, Haitao; Chen, N. H.; Zhang, Q. M.; Su, Yingna; Su, Weiyi

doi:10.3847/1538-4357/aa9073

Cited by 38 publications

(41 citation statements)

References 105 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While loop "B" showed the oscillation pattern as seen from the stack plot along slice "L1" (Figures 4(c)-(d)). The oscillation had an average period of 4 min, in agreement with the typical periods of several minutes for the kink oscillations of coronal loops (Liu & Ofman 2014;Zimovets & Nakariakov 2015;Li et al 2017a). The rising speed of the jet was estimated to be 140−160 km s −1 and the maximum height traced was up to 40 Mm (Figure 4(d)).…”

Section: Dynamics Of the Overlying Loopssupporting

confidence: 81%

Two Episodes of Magnetic Reconnections during a Confined Circular-ribbon Flare

Yang

Zhang

et al. 2018

ApJ

Self Cite

View full text Add to dashboard Cite

We analyze a unique event with an M1.8 confined circular-ribbon flare on 2016 February 13, with successive formations of two circular ribbons at the same location. The flare had two distinct phases of UV and EUV emissions with an interval of about 270 s, of which the second peak was energetically more important. The first episode was accompanied by the eruption of a mini-filament and the fast elongation motion of a thin circular ribbon (CR1) along the counterclockwise direction at a speed of about 220 km s −1 . Two elongated spine-related ribbons were also observed, with the inner ribbon co-temporal with CR1 and the remote brightenings forming ∼ 20 s later. In the second episode, another mini-filament erupted and formed a blowout jet. The second circular ribbon and two spine-related ribbons showed similar elongation motions with that during the first episode. The extrapolated 3D coronal magnetic fields reveal the existence of a fan-spine topology, together with a quasi-separatrix layer (QSL) halo surrounding the fan plane and another QSL structure outlining the inner spine. We suggest that continuous null-point reconnection between the filament and ambient open field occurs in each episode, leading to the sequential opening of the filament and significant shifts of the fan plane footprint. For the first time, we propose a compound eruption model of circular-ribbon flares consisting of two sets of successively formed ribbons and eruptions of multiple filaments in a fan-spine-type magnetic configuration.

show abstract

Section: Dynamics Of the Overlying Loopssupporting

confidence: 81%

Two Episodes of Magnetic Reconnections during a Confined Circular-ribbon Flare

Yang

Zhang

et al. 2018

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both observations find that the kink oscillations in the peak intensity and line width exhibit a very small oscillatory amplitude. This also explains that the timedistance images of peak intensity and line width do not display the obvious oscillations as that of Doppler velocity, because those oscillations overlap on the strong background (see also., Dolla et al, 2012;Li et al, 2017b). Our new observational result is that the kink oscillations within non-damping amplitudes are identified at hot flaring loops, i.e., 11 MK.…”

Section: Discussionmentioning

confidence: 59%

“…The speed is estimated to be about 45 km s −1 , as indicated by the green arrows. This is much smaller than the local sound speed, i.e., about 500 km s −1 at 11 MK (Nakariakov & Ofman, 2001;Kumar et al, 2013;Li et al, 2017b). It could be associated with intermittently evaporated plasma, see also the movie.mp4, which clearly shows the flaring loops in AIA 94 Å and 131 Å propagating and intermittently passing the slit of IRIS.…”

Section: Observations and Data Reductionsmentioning

confidence: 91%

Non-damping oscillations at flaring loops

Yuan

et al. 2018

A&A

Self Cite

View full text Add to dashboard Cite

Context. Quasi-periodic oscillations are usually detected as spatial displacements of coronal loops in imaging observations or as periodic shifts of line properties (i.e., Doppler velocity, line width and intensity) in spectroscopic observations. They are often applied for remote diagnostics of magnetic fields and plasma properties on the Sun. Aims. We combine imaging and spectroscopic measurements of available space missions, and investigate the properties of nondamping oscillations at flaring loops. Methods. We used the Interface Region Imaging Spectrograph (IRIS) to measure the spectrum over a narrow slit. The doublecomponent Gaussian fitting method was used to extract the line profile of Fe xxi 1354.08 Å at the 'O i' spectral window. The quasiperiodicity of loop oscillations were identified in the Fourier and wavelet spectra. Results. A periodicity at about 40 s is detected in the line properties of Fe xxi 1354.08 Å, hard X-ray emissions in GOES 1−8 Å derivative, and Fermi 26−50 keV. The Doppler velocity and line width oscillate in phase, while a phase shift of about π/2 is detected between the Doppler velocity and peak intensity. The amplitudes of Doppler velocity and line width oscillation are about 2.2 km s −1 and 1.9 km s −1 , respectively, while peak intensity oscillate with amplitude at about 3.6% of the background emission. Meanwhile, a quasi-period of about 155 s is identified in the Doppler velocity and peak intensity of the Fe xxi 1354.08 Å line emission, and AIA 131 Å intensity. Conclusions. The oscillations at about 40 s are not damped significantly during the observation, it might be linked to the global kink modes of flaring loops. The periodicity at about 155 s is most likely a signature of recurring downflows after chromospheric evaporation along flaring loops. The magnetic field strengths of the flaring loops are estimated to be about 120−170 G using the MHD seismology diagnostics, which are consistent with the magnetic field modeling results using the flux rope insertion method.

show abstract

“…Interestingly, an increase of the wave period with time was detected, suggesting a continuous generation of fast sausage modes in the gradually longer flaring loops issued from the reconnection process. Another example was provided by Li et al (2017a) with IRIS observations of a fundamental standing kink mode in a M7.1 flare. These waves are characterized by a periodic Doppler signal (with 3.1 minute period) and negligible intensity variation.…”

Section: Magnetic Reconnection In Flaresmentioning

confidence: 99%

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

et al. 2021

View full text Add to dashboard Cite

The Interface Region Imaging Spectrograph (IRIS) has been obtaining near- and far-ultraviolet images and spectra of the solar atmosphere since July 2013. IRIS is the highest resolution observatory to provide seamless coverage of spectra and images from the photosphere into the low corona. The unique combination of near- and far-ultraviolet spectra and images at sub-arcsecond resolution and high cadence allows the tracing of mass and energy through the critical interface between the surface and the corona or solar wind. IRIS has enabled research into the fundamental physical processes thought to play a role in the low solar atmosphere such as ion–neutral interactions, magnetic reconnection, the generation, propagation, and dissipation of waves, the acceleration of non-thermal particles, and various small-scale instabilities. IRIS has provided insights into a wide range of phenomena including the discovery of non-thermal particles in coronal nano-flares, the formation and impact of spicules and other jets, resonant absorption and dissipation of Alfvénic waves, energy release and jet-like dynamics associated with braiding of magnetic-field lines, the role of turbulence and the tearing-mode instability in reconnection, the contribution of waves, turbulence, and non-thermal particles in the energy deposition during flares and smaller-scale events such as UV bursts, and the role of flux ropes and various other mechanisms in triggering and driving CMEs. IRIS observations have also been used to elucidate the physical mechanisms driving the solar irradiance that impacts Earth’s upper atmosphere, and the connections between solar and stellar physics. Advances in numerical modeling, inversion codes, and machine-learning techniques have played a key role. With the advent of exciting new instrumentation both on the ground, e.g. the Daniel K. Inouye Solar Telescope (DKIST) and the Atacama Large Millimeter/submillimeter Array (ALMA), and space-based, e.g. the Parker Solar Probe and the Solar Orbiter, we aim to review new insights based on IRIS observations or related modeling, and highlight some of the outstanding challenges.

show abstract

Doppler Shift Oscillations from a Hot Line Observed by IRIS

Cited by 38 publications

References 105 publications

Two Episodes of Magnetic Reconnections during a Confined Circular-ribbon Flare

Two Episodes of Magnetic Reconnections during a Confined Circular-ribbon Flare

Non-damping oscillations at flaring loops

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

Contact Info

Product

Resources

About