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Since the discovery of quasi-periodic propagating oscillations with periods of order three to ten minutes in coronal loops with TRACE and EIT (later with EUVI and EIS), they have been almost universally interpreted as evidence for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Bart De Pontieu , Scott W. McIntosh

The excitation of Alfvenic waves in the solar spicules due to the localized Alfvenic pulse is investigated. A set of incompressible MHD equations in two dimensional $x-z$ plane with steady flows and sheared magnetic fields is solved.…

Solar and Stellar Astrophysics · Physics 2015-06-15 H. Ebadi , M. Hosseinpour , Z. Fazel

M dwarf's atmosphere and wind is expected to be highly magnetized. The nonlinear propagation of Alfv\'en wave could play a key role in both heating the stellar atmosphere and driving the stellar wind. Along this Alfv\'en wave scenario, we…

Solar and Stellar Astrophysics · Physics 2021-01-20 Takahito Sakaue , Kazunari Shibata

The radio continuum spectra of 14 star-forming galaxies are investigated by fitting nonthermal (synchrotron) and thermal (free-free) radiation laws. The underlying radio continuum measurements cover a frequency range of ~325 MHz to 24.5 GHz…

Astrophysics of Galaxies · Physics 2018-03-28 Uli Klein , Ute Lisenfeld , Simon Verley

Convective motions in the solar atmosphere cause spectral lines to become asymmetric and shifted in wavelength. For photospheric lines, this differential Doppler shift varies from the solar disk center to the limb. Precise and comprehensive…

Solar and Stellar Astrophysics · Physics 2019-04-10 Johannes Löhner-Böttcher , Wolfgang Schmidt , Rolf Schlichenmaier , Tilo Steinmetz , Ronald Holzwarth

Observational detection of quasi-periodic drifting fine structures in a type III radio burst associated with a solar flare SOL2015-04-16T11:22, with Low Frequency Array, is presented. Although similar modulations of the type III emission…

Solar and Stellar Astrophysics · Physics 2018-07-11 Dmitrii Y. Kolotkov , Valery M. Nakariakov , Eduard P. Kontar

Eruptive activity in the solar corona can often lead to the propagation of shock waves. In the radio domain the primary signature of such shocks are type II radio bursts, observed in dynamic spectra as bands of emission slowly drifting…

Cyclotron resonance scattering features observed in the spectra of some X-ray pulsars show significant changes of the line energy with the pulsar luminosity. At high luminosities, these variations are often associated with the onset and…

This paper reviews our growing understanding of the physics behind coronal heating (in open-field regions) and the acceleration of the solar wind. Many new insights have come from the last solar cycle's worth of observations and theoretical…

Solar and Stellar Astrophysics · Physics 2010-02-02 Steven R. Cranmer , John L. Kohl , Mari Paz Miralles , Adriaan A. van Ballegooijen

To study the dynamics of coronal holes and the role of waves in the acceleration of the solar wind, spectral observations were performed over polar coronal hole regions with the SUMER spectrometer on SoHO and the EIS spectrometer on Hinode.…

Solar and Stellar Astrophysics · Physics 2009-05-08 D. Banerjee , L. Teriaca , G. R. Gupta , S. Imada , G. Stenborg , S. K. Solanki

Kinetic Alfven wave turbulence in solar wind is considered and it is shown that non-Maxwellian electron distribution function has a significant effect on the dynamics of the solar wind plasmas. Linear Landau damping leads to the formation…

Solar and Stellar Astrophysics · Physics 2015-05-19 Leonid Rudakov , Manish Mithaiwala , Gurudas Ganguli , Chris Crabtree

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

The solar corona is orders of magnitude hotter than the underlying photosphere, but how the corona attains such high temperatures is still not understood. Soft X-ray (SXR) emission provides important diagnostics for thermal processes in the…

Solar and Stellar Astrophysics · Physics 2015-09-15 Amir Caspi , Thomas N. Woods , Harry P. Warren

Ultralight dark photons and axions are well-motivated hypothetical dark matter candidates. Both dark photon dark matter and axion dark matter can resonantly convert into electromagnetic waves in the solar corona when their mass is equal to…

High Energy Physics - Phenomenology · Physics 2024-02-02 Haipeng An , Xingyao Chen , Shuailiang Ge , Jia Liu , Yan Luo

The Type-II solar radio burst recorded on 13 June 2010 by the radio spectrograph of the Hiraiso Solar Observatory was employed to estimate the magnetic-field strength in the solar corona. The burst was characterized by a well pronounced…

Solar and Stellar Astrophysics · Physics 2015-06-15 V. Vasanth , S. Umapathy , B. Vršnak , T. Žic , O. Prakash

A canonical description of a corotating solar wind high speed stream, in terms of velocity profile, would indicate three main regions:a stream interface or corotating interaction region characterized by a rapid flow speed increase and by…

Alfv\'enic waves have gained renewed interest since the existence of ubiquitous propagating kink waves were discovered in the corona. {It has long been suggested that Alfv\'enic} waves play an important role in coronal heating and the…

Solar and Stellar Astrophysics · Physics 2019-05-15 Ajay K. Tiwari , Richard J. Morton , Stephane Régnier , James A. McLaughlin

We present simulation results of the impulsively generated linear and non-linear Alfv\'en waves in the weakly curved coronal magnetic flux-tubes (coronal funnels) and discuss their implications for the coronal heating and solar wind…

Solar and Stellar Astrophysics · Physics 2023-07-19 P. Chmielewski , A. K. Srivastava , K. Murawski , Z. E. Musielak

The present spectroscopic study of the ultraviolet coronal emission in a polar hole, detected on April 6-9, 1996 with the Ultraviolet Coronagraph Spectrometer aboard the SOHO spacecraft, identifies the inter-plume lanes and background…

Astrophysics · Physics 2009-10-31 S. Giordano , E. Antonucci , G. Noci , M. Romoli , J. L. Kohl

In the corona, plasma is accelerated to hundreds of kilometers per second, and heated to temperatures hundreds of times hotter than the Sun's surface, before it escapes to form the solar wind. Decades of space-based experiments have shown…

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