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Related papers: Active region upflows: 1. Multi-instrument observa…

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We investigate a small-scale ($\approx$ 1.5 Mm along the slit), supersonic downflow of about 90 km s$^{-1}$ in the transition region above the light-bridged sunspot umbra in AR 11836. The observations were obtained with the Interface Region…

Solar and Stellar Astrophysics · Physics 2015-10-21 Thomas Straus , Bernhard Fleck , Vincenzo Andretta

Emerging dimming occurs in isolated solar active regions (ARs) during the early stages of magnetic flux emergence. Observed by the Atmospheric Imaging Assembly, it features a rapid decrease in extreme-ultraviolet (EUV) emission in the 171…

Solar and Stellar Astrophysics · Physics 2021-05-05 Anna V. Payne , Xudong Sun

We investigate the ratio of the vertical and horizontal velocities of the photospheric plasma flows in the region of emerging magnetic fields on the Sun. We carried out a study of photospheric velocities during the first hours of the…

Solar and Stellar Astrophysics · Physics 2012-12-17 A. Khlystova

We investigate intensity variations and energy deposition in five coronal loops in active region cores. These were selected for their strong variability in the AIA/SDO 94 {\AA} intensity channel. We isolate the hot Fe XVIII and Fe XXI…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. C. Cadavid , J. K. Lawrence , D. J. Christian , D. B. Jess , G. Nigro

Spicules are the thin hair/grass-like structures that are prominently observed at the chromospheric solar limb. It is believed that fibrils and rapid blueshifted and redshifted excursions (RBEs and RREs; collectively referred to as REs)…

Solar and Stellar Astrophysics · Physics 2024-08-09 Ravi Chaurasiya , Ankala Raja Bayanna , R. E. Louis , T. M. D. Pereira , S. K. Mathew

This paper presents a detailed study of chromospheric evaporation using the EUV Imaging Spectrometer (EIS) onboard Hinode in conjunction with HXR observations from RHESSI. The advanced capabilities of EIS were used to measure Doppler shifts…

Solar and Stellar Astrophysics · Physics 2015-05-13 Ryan O. Milligan , Brian R. Dennis

Investigating the outflows emanating from young stellar objects (YSOs) on sub-arcsecond scales provides important clues to the nature of the underlying accretion-ejection process occurring near the central protostar. We have investigated…

Solar and Stellar Astrophysics · Physics 2015-06-19 Marc C. White , Peter J. McGregor , Geoffrey V. Bicknell , Raquel Salmeron , Tracy L. Beck

Quasi-periodic disturbances have been observed in the outer solar atmosphere for many years now. Although first interpreted as upflows (Schrijver et al. (1999)), they have been widely regarded as slow magnetoacoustic waves, due to observed…

Solar and Stellar Astrophysics · Physics 2015-06-05 G. Kiddie , I. De Moortel , G. Del Zanna , S. W. McIntosh , I. Whittaker

Slow magnetoacoustic waves with a 3 minute period are upward-propagating waves traveling through the density-stratified umbral atmosphere. The decreasing density causes their amplitude to increase, developing into nonlinear waves through…

Solar and Stellar Astrophysics · Physics 2025-07-15 Y. Sanjay , S. Krishna Prasad , R. Sych , P. S. Rawat

Solar active regions are associated with Evershed outflows in sunspot penumbrae, moat outflows surrounding sunspots, and extended inflows surrounding active regions. The latter have been identified on established active regions by various…

Solar and Stellar Astrophysics · Physics 2021-09-01 N. Gottschling , H. Schunker , A. C. Birch , B. Löptien , L. Gizon

We present observations of high temperature emission in the core of a solar active region using instruments on Hinode and SDO. These multi-instrument observations allow us to determine the distribution of plasma temperatures and follow the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Harry P. Warren , David H. Brooks , Amy R. Winebarger

Dynamics of hot chromospheric plasma of solar flares is a key to understanding of mechanisms of flare energy release and particle acceleration. A moderate M1.0 class flare of 12 June, 2014 (SOL2014-06-12T21:12) was simultaneously observed…

The emergence of active regions (ARs) closely relates to the solar dynamo and the dynamical atmospheric phenomena.With high-resolution and long-lasting observations from the New Vacuum Solar Telescope, we report a new dynamic activity…

Solar and Stellar Astrophysics · Physics 2019-09-25 Sihui Zhong , Yijun Hou , Leping Li , Jun Zhang , Yongyuan Xiang

We present observations of persistent oscillations of some bright features in the upper-chromosphere/transition-region above sunspots taken by IRIS SJ 1400 {\AA} and upward propagating quasi-periodic disturbances along coronal loops rooted…

Solar and Stellar Astrophysics · Physics 2018-03-21 Zhenyong Hou , Zhenghua Huang , Lidong Xia , Bo Li , Hui Fu

We present new measurements of the time variability of intensity, Doppler and non-thermal velocities in moss in an active region core observed by the EUV Imaging Spectrometer on Hinode in 2007, June. The measurements are derived from…

Solar and Stellar Astrophysics · Physics 2009-09-28 David H. Brooks , Harry P. Warren

Solar active regions (ARs) that produce major flares typically exhibit strong plasma shear flows around photospheric magnetic polarity inversion lines (MPILs). It is therefore important to quantitatively measure such photospheric shear…

Solar and Stellar Astrophysics · Physics 2018-10-29 Sung-Hong Park , Jordan A. Guerra , Peter T. Gallagher , Manolis K. Georgoulis , D. Shaun Bloomfield

We present the results of our mosaic observations of a single Class 0 protostar IRAS 15398$-$3359 with Atacama Compact Array (ACA) in the CO $J=2\mbox{-}1$ line. The new observations covering a $\sim\!2'$ square region revealed elongated…

Solar and Stellar Astrophysics · Physics 2024-03-19 Jinshi Sai , Hsi-Wei Yen , Masahiro N. Machida , Nagayoshi Ohashi , Yusuke Aso , Anaëlle J. Maury , Sébastien Maret

For a solar flare occurring on 2010 November 3, we present observations using several SDO/AIA extreme-ultraviolet (EUV) passbands of an erupting flux rope followed by inflows sweeping into a current sheet region. The inflows are soon…

Solar and Stellar Astrophysics · Physics 2015-06-03 S. L. Savage , G. Holman , K. K. Reeves , D. B. Seaton , D. E. McKenzie , Y. Su

The chemical composition of the solar corona is different from that of the solar photosphere, with the strongest variation being observed in active regions (ARs). Using data from the Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) on…

Aims: We investigate the temporal evolution of magnetic flux emergence in the quiet Sun atmosphere close to disk center. Methods: We combine high-resolution SoHO/MDI magnetograms with TRACE observations taken in the 1216 {\AA} channel in…

Solar and Stellar Astrophysics · Physics 2015-06-16 P. Gömöry , H. Balthasar , K. G. Puschmann