Browsing Institutt for teoretisk astrofysikk by Author "Gudiksen, Boris Vilhelm"

Now showing items 1-14 of 14

  • Accelerated particle beams in a 3D simulation of the quiet Sun 
    Frogner, Lars; Gudiksen, Boris Vilhelm; Bakke, Helle (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    Context. Observational and theoretical evidence suggest that beams of accelerated particles are produced in flaring events of all sizes in the solar atmosphere, from X-class flares to nanoflares. Current models of these ...
  • Accelerated particle beams in a 3D simulation of the quiet Sun: Effects of advanced beam propagation modelling 
    Frogner, Lars; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
    Context. Charged particles are constantly accelerated to non-thermal energies by the reconnecting magnetic field in the solar atmosphere. Our understanding of the interactions between the accelerated particles and their ...
  • Accelerated particle beams in a 3D simulation of the quiet Sun: Lower atmospheric spectral diagnostics 
    Bakke, Helle; Frogner, Lars; Rouppe van der Voort, Luc; Gudiksen, Boris Vilhelm; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Context. Nanoflare heating through small-scale magnetic reconnection events is one of the prime candidates to explain heating of the solar corona. However, direct signatures of nanoflares are difficult to determine, and ...
  • Chromospheric emission from nanoflare heating in RADYN simulations 
    Bakke, Helle; Carlsson, Mats; Rouppe van der Voort, Luc; Gudiksen, Boris Vilhelm; Polito, V.; Testa, Paola; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Context. Heating signatures from small-scale magnetic reconnection events in the solar atmosphere have proven to be difficult to detect through observations. Numerical models that reproduce flaring conditions are essential ...
  • Disentangling flows in the solar transition region 
    Zacharias, Pia; Hansteen, Viggo; Leenaarts, Jorrit; Carlsson, Mats; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: The measured average velocities in solar and stellar spectral lines formed at transition region temperatures have been difficult to interpret. The dominant redshifts observed in the lower transition region naturally ...
  • Emission of Joule heating events in simulations of the solar corona 
    Kanella, Charalambos; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Context. Nanoscale events in cooperation with steady heating from a slow heating mechanism, such as slow-burning current-sheets, could be able to heat the corona; however, their observational traces are hard to detect via ...
  • Identification of coronal heating events in 3D simulations 
    Kanella, Charalambos; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Context. The solar coronal heating problem has been an open question in the science community since 1939. One of the proposed models for the transport and release of mechanical energy generated in the sub-photospheric ...
  • Investigating 4D coronal heating events in magnetohydrodynamic simulations 
    Kanella, Charalambos; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: One candidate model for heating the solar corona is magnetic reconnection that embodies Ohmic dissipation of current sheets. When numerous small-scale magnetic reconnection events occur, then it is possible to ...
  • Non-thermal electrons from solar nanoflares In a 3D radiative MHD simulation 
    Bakke, Helle; Frogner, Lars; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: We introduce a model for including accelerated particles in pure magnetohydrodynamics (MHD) simulations of the solar atmosphere. Aims: We show that the method is viable and produces results that enhance the realism ...
  • On the Origin of the Magnetic Energy in the Quiet Solar Chromosphere 
    Martinez-Sykora, Juan; Hansteen, Viggo; Gudiksen, Boris Vilhelm; Carlsson, Mats; De Pontieu, Bart Walter; Gošić, Milan (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    The presence of magnetic field is crucial in the transport of energy through the solar atmosphere. Recent ground-based and space-borne observations of the quiet Sun have revealed that magnetic field accumulates at photospheric ...
  • A publicly available simulation of an enhanced network region of the Sun 
    Carlsson, Mats; Hansteen, Viggo; Gudiksen, Boris Vilhelm; Leenaarts, Jorrit; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    Context. The solar chromosphere is the interface between the solar surface and the solar corona. Modelling of this region is difficult because it represents the transition from optically thick to thin radiation escape, ...
  • Synthesized spectra of optically thin emission lines produced by the Bifrost stellar atmosphere code, including nonequilibrium ionization effects: A study of the intensity, nonthermal line widths, and Doppler shifts 
    Olluri, Kosovare; Gudiksen, Boris Vilhelm; Hansteen, Viggo; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    In recent years realistic 3D numerical models of the solar atmosphere have become available. The models attempt to recreate the solar atmosphere and mimic observations in the best way, in order to make it possible to couple ...
  • TIME DEPENDENT NONEQUILIBRIUM IONIZATION of TRANSITION REGION LINES OBSERVED with IRIS 
    Martinez-Sykora, Juan; De Pontieu, Bart Walter; Hansteen, Viggo; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    The properties of nonstatistical equilibrium ionization of silicon and oxygen ions are analyzed in this work. We focus on five solar targets (quiet Sun; coronal hole; plage; quiescent active region, AR; and flaring AR) as ...
  • Two-dimensional Radiative Magnetohydrodynamic Simulations of Partial Ionization in the Chromosphere. II. Dynamics and Energetics of the Low Solar Atmosphere 
    Martinez-Sykora, Juan; De Pontieu, Bart Walter; Carlsson, Mats; Hansteen, Viggo; Nobrega-Siverio, Daniel; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    We investigate the effects of interactions between ions and neutrals on the chromosphere and overlying corona using 2.5D radiative MHD simulations with the Bifrost code. We have extended the code capabilities implementing ...