Now showing items 1-20 of 49

  • Are tornado-like magnetic structures able to support solar prominence plasma? 

    Luna, M.; Moreno-Insertis, F.; Priest, E. (2015-07-20) - Journal article
    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by ...
  • Bombs and flares at the surface and lower atmosphere of the Sun 

    Hansteen, V. H.; Archontis, V.; Pereira, T. M. D.; Carlsson, M.; Rouppe van der Voort, L.; Leenaarts, J. (2017-04-10) - Journal article
    A spectacular manifestation of solar activity is the appearance of transient brightenings in the far wings of the Hα line, known as Ellerman bombs (EBs). Recent observations obtained by the Interface Region Imaging ...
  • Can substorm particle acceleration be applied to solar flares? 

    Birn, Joachim; Battaglia, Marina; Fletcher, Lyndsay; Hesse, Michael; Neukirch, Thomas (2017-10-20) - Journal article
    Using test particle studies in the electromagnetic fields of three-dimensional magnetohydrodynamic (MHD) simulations of magnetic reconnection, we study the energization of charged particles in the context of the standard ...
  • Catastrophe versus instability for the eruption of a toroidal solar magnetic flux rope 

    Kliem, B.; Lin, J.; Forbes, T. G.; Priest, E. R.; Toeroek, T. (2014-07-01) - Journal article
    The onset of a solar eruption is formulated here as either a magnetic catastrophe or as an instability. Both start with the same equation of force balance governing the underlying equilibria. Using a toroidal flux rope in ...
  • Clusters of small eruptive flares produced by magnetic reconnection in the Sun 

    Archontis, V.; Hansteen, V. (2014-06-10) - Journal article
    We report on the formation of small solar flares produced by patchy magnetic reconnection between interacting magnetic loops. A three-dimensional (3D) magnetohydrodynamic (MHD) numerical experiment was performed, where a ...
  • Comparison of methods for modelling coronal magnetic fields 

    Goldstraw, E. E.; Hood, A. W.; Browning, P. K.; Cargill, P. J. (2018-02-26) - Journal article
    Aims. Four different approximate approaches used to model the stressing of coronal magnetic fields due to an imposed photospheric motion are compared with each other and the results from a full time-dependent magnetohydrodynamic ...
  • A complex solar coronal jet with two phases 

    Chen, Jie; Su, Jiangtao; Deng, Yuanyong; Priest, E. R. (2017-05-04) - Journal article
    Jets often occur repeatedly from almost the same location. In this paper, a complex solar jet was observed with two phases to the west of NOAA AR 11513 on 2012 July 2. If it had been observed at only moderate resolution, ...
  • Contribution of mode-coupling and phase-mixing of Alfvén waves to coronal heating 

    Pagano, P.; De Moortel, I. (2017-05-12) - Journal article
    Context. Phase-mixing of Alfvén waves in the solar corona has been identified as one possible candidate to explain coronal heating. While this scenario is supported by observations of ubiquitous oscillations in the corona ...
  • Coronal energy release by MHD avalanches : continuous driving 

    Reid, Jack; Hood, Alan William; Parnell, Clare Elizabeth; Browning, P. K.; Cargill, Peter (2018-03-23) - Journal article
    Previous work has confirmed the concept of a magnetohydrodynamic (MHD) avalanche in pre-stressed threads within a coronal loop. We undertook a series of full, three-dimensional MHD simulations in order to create three ...
  • Coronal heating in multiple magnetic threads 

    Tam, Kuan Vai; Hood, Alan William; Browning, Philippa; Cargill, Peter (2015-08) - Journal article
    Context. Heating the solar corona to several million degrees requires the conversion of magnetic energy into thermal energy. In this paper, we investigate whether an unstable magnetic thread within a coronal loop can ...
  • The dependence of coronal loop heating on the characteristics of slow photospheric motions 

    Ritchie, M. L.; Wilmot-Smith, A. L.; Hornig, G. (2016-06-06) - Journal article
    The Parker hypothesis assumes that heating of coronal loops occurs due to reconnection, induced when photospheric motions braid field lines to the point of current sheet formation. In this contribution we address the ...
  • Dynamic properties of bright points in an active region 

    Keys, P.H.; Mathioudakis, M.; Jess, D.B.; MacKay, D.H.; Keenan, F.P. (2014-06-20) - Journal article
    Context. Bright points (BPs) are small-scale, magnetic features ubiquitous across the solar surface. Previously, we have observed and noted their properties for quiet Sun regions. Here, we determine the dynamic properties ...
  • Emergence of non-twisted magnetic fields in the Sun : jets and atmospheric response 

    Syntelis, P.; Archontis, V.; Gontikakis, C.; Tsinganos, K. (2015-12) - Journal article
    Aims. We study the emergence of a non-twisted flux tube from the solar interior into the solar atmosphere. We investigate whether the length of the buoyant part of the flux tube (i.e. λ) affects the emergence of the field ...
  • The emergence of weakly twisted magnetic fields in the Sun 

    Archontis, Vasilis; Hood, Alan William; Tsinganos, K (2013-11-01) - Journal article
    We have studied the emergence of a weakly twisted magnetic flux tube from the upper convection zone into the solar atmosphere. It is found that the rising magnetized plasma does not undergo the classical, single Ω-shaped ...
  • Energetics of the Kelvin-Helmholtz instability induced by transverse waves in twisted coronal loops 

    Howson, T. A.; De Moortel, I.; Antolin, P. (2017-11-16) - Journal article
    Aims. We quantify the effects of twisted magnetic fields on the development of the magnetic Kelvin-Helmholtz instability (KHI) in transversely oscillating coronal loops. Methods. We modelled a fundamental standing kink ...
  • The eruption of a small-scale emerging flux rope as the driver of an M-class flare and of a coronal mass ejection 

    Yan, X. L.; Jiang, C. W.; Xue, Z. K.; Wang, J. C.; Priest, E. R.; Yang, L. H.; Kong, D. F.; Cao, W. D.; Ji, H. S. (2017-08-10) - Journal article
    Solar flares and coronal mass ejections are the most powerful explosions in the Sun. They are major sources of potentially destructive space weather conditions. However, the possible causes of their initiation remain ...
  • Fast approximate radiative transfer method for visualizing the fine structure of prominences in the hydrogen Hα line 

    Heinzel, P.; Gunár, S.; Anzer, U. (2015-07) - Journal article
    Aims. We present a novel approximate radiative transfer method developed to visualize 3D whole-prominence models with multiple fine structures using the hydrogen Hα spectral line. Methods. This method employs a fast ...
  • Flare particle acceleration in the interaction of twisted coronal flux ropes 

    Threlfall, J.; Hood, A. W.; Browning, P. K. (2018-03-20) - Journal article
    Aims. The aim of this work is to investigate and characterise non-thermal particle behaviour in a three-dimensional (3D) magnetohydrodynamical (MHD) model of unstable multi-threaded flaring coronal loops. Methods.  We have ...
  • The heating of solar coronal loops by Alfvèn wave turbulence 

    van Ballegooijen, A. A.; Asgari-Targhi, M.; Voss, A. (2017-10-30) - Journal article
    In this paper we further develop a model for the heating of coronal loops by Alfvèn wave turbulence (AWT). The Alfvèn waves are assumed to be launched from a collection of kilogauss flux tubes in the photosphere at the two ...
  • Helical blowout jets in the sun : untwisting and propagation of waves 

    Lee, E.J.; Archontis, V.; Hood, A.W. (2015-01-01) - Journal article
    We report on a numerical experiment of the recurrent onset of helical "blowout" jets in an emerging flux region. We find that these jets are running with velocities of ∼100-250 km s-1 and they transfer a vast amount of ...