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We present a detailed analysis of oxygen ion velocity distributions in the extended solar corona, based on observations made with the Ultraviolet Coronagraph Spectrometer (UVCS) on the SOHO spacecraft. Polar coronal holes at solar minimum…

Astrophysics · Physics 2009-11-13 Steven R. Cranmer , Alexander V. Panasyuk , John L. Kohl

We found that oscillations of LOS velocity in H-alpha are different for various parts of faculae regions. Power spectra show that the contribution of low-frequency modes (1.2 - 2 mHz) increase at the network boundaries. Three and five-…

Solar and Stellar Astrophysics · Physics 2011-10-10 N. I. Kobanov , V. A. Pulyaev

Solar torsional oscillations are migrating bands of slower- and faster-than-average rotation, which are strongly related to the Sun's magnetic cycle. We perform a long-term study (16 yr) of hemispherical asymmetry in solar torsional…

Solar and Stellar Astrophysics · Physics 2018-08-01 Lekshmi B , Dibyendu Nandy , H M Antia

Rapidly decaying long-period oscillations often occur in hot coronal loops of active regions associated with small (or micro-) flares. This kind of wave activity was first discovered with the SOHO/SUMER spectrometer from Doppler velocity…

Solar and Stellar Astrophysics · Physics 2021-10-01 Tongjiang Wang , Leon Ofman , Ding Yuan , Fabio Reale , Dmitrii Y. Kolotkov , Abhishek K. Srivastava

The heating of the lower solar corona is examined using numerical simulations and theoretical models of magnetohydrodynamic turbulence in open magnetic regions. A turbulent energy cascade to small length scales perpendicular to the mean…

Astrophysics · Physics 2009-11-07 P. Dmitruk , W. H. Matthaeus , L. J. Milano , S. Oughton , G. P. Zank , D. J. Mullan

Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. Pierrard , K. Borremans , J. F. Lemaire

The umbral regions of sunspots and pores in the solar photosphere are generally dominated by $3$~mHz oscillations, which are due to $p$-modes penetrating the magnetic region. In these locations, wave power is also significantly reduced with…

Decayless kink oscillations of solar coronal loops (or decayless oscillations for short) have attracted great attention since their discovery. Coronal bright points (CBPs) are mini-active regions and consist of loops with a small size.…

Solar and Stellar Astrophysics · Physics 2022-05-18 Yuhang Gao , Hui Tian , Tom Van Doorsselaere , Yajie Chen

Solar radio spikes are short duration and narrow bandwidth fine structures in dynamic spectra observed from GHz to tens of MHz range. Their very short duration and narrow frequency bandwidth are indicative of sub-second small-scale energy…

Solar and Stellar Astrophysics · Physics 2021-08-31 Daniel L. Clarkson , Eduard P. Kontar , Mykola Gordovskyy , Nicolina Chrysaphi , Nicole Vilmer

The solar corona has been revealed in the past decade to be a highly dynamic nonequilibrium plasma environment. Both the loop-filled coronal base and the extended acceleration region of the solar wind appear to be strongly turbulent, but…

Astrophysics · Physics 2008-11-26 Steven R. Cranmer

In this work we selected one particular fibril from a high resolution solar chromosphere observation from the Dutch Open Telescope, and tried to obtain a broad picture of the intricate mechanism that might be incorporated in the multiple…

Solar and Stellar Astrophysics · Physics 2015-11-11 Emanuel Sungging Mumpuni , Dhani Herdiwijaya , Mitra Djamal , Thomas Djamaluddin

At the site of their origin, solar meterwave radio bursts contain pristine information about the local coronal magnetic field and plasma parameters. On its way through the turbulent corona, this radiation gets substantially modified due to…

Solar and Stellar Astrophysics · Physics 2019-05-01 Atul Mohan , Surajit Mondal , Divya Oberoi , Colin Lonsdale

Observations of a large solar flare of December 13, 2006, using Solar Optical Telescope (SOT) on Hinode spacecraft revealed high-frequency oscillations excited by the flare in the sunspot chromosphere. These oscillations are observed in the…

Astrophysics · Physics 2009-11-13 A. G. Kosovichev , T. Sekii

Oscillations in the solar atmosphere have long been observed in quiet conditions, and increasingly also in data taken during solar flares. The chromosphere is known for its 3-minute signals, which are particularly strong over sunspot…

Solar and Stellar Astrophysics · Physics 2021-03-17 David C. L. Millar , Lyndsay Fletcher , Ryan O. Milligan

We present a study of wave processes occurring in solar active region NOAA 11131 on 2010 December 10, captured by the Solar Dynamics Observatory in the 1600A, 304A, and 171A channels. For spectral analysis we employed pixelised wavelet…

Solar and Stellar Astrophysics · Physics 2021-01-20 Robert Sych , David B. Jess , Jiangtao Su

We present evidence of hitherto undiscovered global-scale oscillations in the near-surface shear layer of the Sun. These oscillations are seen as large scale variations of radial shear in both the zonal and meridional flows relative to…

Solar and Stellar Astrophysics · Physics 2023-07-05 Richard S. Bogart , Charles S. Baldner , Sarbani Basu , Rachel Howe , Maria Cristina Rabello Soares

We detected peaks of oscillatory power at 3 and ~6.5 minutes in the umbra of the central sunspot of the active region NOAA AR 10707 in data obtained in the near infrared (NIR) continuum at 1565.7 nm. The NIR dataset captured umbral dynamics…

Solar and Stellar Astrophysics · Physics 2015-05-28 A. Andic , W. Cao , P. R. Goode

Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from…

Solar and Stellar Astrophysics · Physics 2015-12-15 Judith de Patoul , Claire Foullon , Pete Riley

Oscillations are abundant in the solar corona. Coronal loop oscillations are typically studied using highly idealised models of magnetic flux tubes. In order to improve our understanding of coronal oscillations, it is necessary to consider…

Solar and Stellar Astrophysics · Physics 2023-08-02 P. Kohutova , P. Antolin , M. Szydlarski , M. Carlsson

The observed features of the radio sources indicate complex propagation effects embedded in the waves of solar radio bursts. In this work, we perform ray-tracing simulations on radio wave transport in the corona and interplanetary region…

Solar and Stellar Astrophysics · Physics 2021-03-24 PeiJin Zhang , ChuanBing Wang , Eduard P. Kontar