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Related papers: Small-scale flows in SUMER and TRACE high-cadence …

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We observed rapid variability ($\lesssim 60$ s) at the footpoints of transient hot ($\sim 8-10$ MK) coronal loops in active region cores, with the Interface Region Imaging Spectrograph (IRIS). The high spatial ($\sim 0.33$ arcsec) and…

Solar and Stellar Astrophysics · Physics 2020-02-12 Paola Testa , Vanessa Polito , Bart De Pontieu

Upflows and downflows at active region (AR) boundaries have been frequently observed with spectroscopic observations at extreme ultraviolet (EUV) passbands. In this paper, we report the coexistence of upflows and downflows at the AR…

Solar and Stellar Astrophysics · Physics 2024-03-13 Yuchuan Wu , Zhenyong Hou , Wenxian Li , Xianyong Bai , Yongliang Song , Xiao Yang , Ziyao Hu , Yuanyong Deng , Kaifan Ji

Small-scale magnetic fields are thought to play an important role in the heating of the outer solar atmosphere. By taking advantage of the unprecedented high-spatial and temporal cadence of IMaX, the filter vector polarimeter on board the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Stangalini , S. K. Solanki , R. Cameron , V. Martìnez Pillet

Coronal loops on the east limb of the Sun were observed by SUMER on SOHO for several days. Small flare-like brightenings are detected very frequently in the hot flare line Fe~{\small XIX}. We find that the relatively intense events are in…

Solar and Stellar Astrophysics · Physics 2015-10-02 T. J. Wang , D. E. Innes , S. K. Solanki , W. Curdt

Context: One of the most prominent processes suggested to heat the corona to well above 10^6 K builds on nanoflares, short bursts of energy dissipation. Aims: We compare observations to model predictions to test the validity of the…

Solar and Stellar Astrophysics · Physics 2015-11-04 Leping Li , Hardi Peter , Feng Chen , Jun Zhang

Context: The atmosphere of the quiet Sun is controlled by photospheric flows sweeping up concentrations of mixed polarity magnetic field. Along supergranule boundaries and junctions, there is a strong correlation between magnetic flux and…

Astrophysics · Physics 2009-11-13 D. E. Innes , A. Genetelli , R. Attie , H. E. Potts

Thermal non-equilibrium (TNE) is a phenomenon that can occur in solar coronal loops when the heating is quasi-constant and highly-stratified. Under such heating conditions, coronal loops undergo cycles of evaporation and condensation. The…

Solar and Stellar Astrophysics · Physics 2019-12-25 C. Froment , P. Antolin , V. M. J. Henriques , P. Kohutova , L. H. M. Rouppe van der Voort

We analyse an absorption event within the H$\alpha$ line wings, identified as a surge, and the co-spatial evolution of an EUV brightening, with spatial and temporal scales analogous to a small blinker. We conduct a multi-wavelength,…

Solar and Stellar Astrophysics · Physics 2015-06-17 C. J. Nelson , J. G. Doyle

Evidence of flare induced, large-amplitude, decay-less transverse oscillations is presented. A system of multi-thermal coronal loops as observed with the Atmospheric Imaging Assembly (AIA), exhibit decay-less transverse oscillations after a…

Solar and Stellar Astrophysics · Physics 2021-08-04 Sudip Mandal , Hui Tian , Hardi Peter

Previous observations have not been able to exclude the possibility that high temperature active region loops are actually composed of many small scale threads that are in various stages of heating and cooling and only appear to be in…

Solar and Stellar Astrophysics · Physics 2014-11-20 Harry P. Warren , Amy R. Winebarger , David H. Brooks

As the interface between the Sun's photosphere and corona, the chromosphere and transition region play a key role in the formation and acceleration of the solar wind. Observations from the Interface Region Imaging Spectrograph reveal the…

Two sequences of solar images obtained by the Transition Region and Coronal Explorer in three UV passbands are studied using wavelet and Fourier analysis and compared to the photospheric magnetic flux measured by the Michelson Doppler…

Spectroscopic observations of the emission lines formed in the solar transition region (TR) commonly show persistent downflows of the order of 10--15 km/s. The cause of such downflows, however, is still not fully clear and has remained a…

The Extreme ultraviolet Imaging Spectrometer (EIS) on board Hinode is the first solar telescope to obtain wide slit spectral images that can be used for detecting Doppler flows in transition region and coronal lines on the Sun and to relate…

Astrophysics · Physics 2009-11-13 D. E. Innes , R. Attie , H. Hara , M. S. Madjarska

Spicules have been proposed as significant contributors to the mass and energy balance of the corona. While previous observations have provided a glimpse of short-lived transient brightenings in the corona that are associated with spicules,…

Solar and Stellar Astrophysics · Physics 2017-10-19 Bart De Pontieu , Ineke De Moortel , Juan Martinez-Sykora , Scott McIntosh

Small-scale transient phenomena in the quiet Sun are believed to play an important role in coronal heating and solar wind generation. One of them named as "X-ray jet" is the subject of our study. We indent to investigate the dynamics,…

Solar and Stellar Astrophysics · Physics 2015-05-19 M. S. Madjarska

Using mainly the 1600 angstrom continuum channel, and also the 1216 angstrom Lyman-alpha channel (which includes some UV continuum and C IV emission), aboard the TRACE satellite, we observed the complete lifetime of a transient, bright…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. M. Pasachoff , E. D. Tingle , I. E. Dammasch , A. C. Sterling

We examine the role of small-scale transients in the formation and evolution of solar coronal plumes. We study the dynamics of plume footpoints seen in the vicinity of a coronal hole using the Atmospheric Imaging Assembly (AIA) images, the…

Solar and Stellar Astrophysics · Physics 2015-05-19 Vaibhav Pant , Laurent Dolla , Rakesh Mazumder , Dipankar Banerjee , S. Krishna Prasad , Vemareddy Panditi

We present the first observational study of the onset and evolution of solar flare turbulence in the lower solar atmosphere on an unprecedented time scale of 1.7 s using the Interface Region Imaging Spectrograph observing plasma at a…

Solar and Stellar Astrophysics · Physics 2018-12-27 N. L. S. Jeffrey , L. Fletcher , N. Labrosse , P. J. A. Simões

Transition-region explosive events (EEs) are characterized by non-Gaussian line profiles with enhanced wings at Doppler velocities of 50-150 km/s. They are believed to be the signature of solar phenomena that are one of the main…

Solar and Stellar Astrophysics · Physics 2016-11-15 Z. Huang , M. S. Madjarska , E. M. Scullion , L. -D. Xia , J. G. Doyle , T. Ray