Browsing Department of Materials Science and Metallurgy by Subject "MHD"

Now showing items 1-10 of 10

  • Destruction of large-scale magnetic field in nonlinear simulations of the shear dynamo 

    Teed, Robert John; Proctor, Michael Richard (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-03-03)
    The Sun's magnetic field exhibits coherence in space and time on much larger scales than the turbulent convection that ultimately powers the dynamo. In the past the α-effect (mean-field) concept has been used to model the ...

  • Gravitoturbulence in magnetized protostellar discs 

    Riols, A; Latter, Henrik Nils (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-05-11)
    Gravitational instability (GI) features in several aspects of protostellar disc evolution, most notably in angular momentum transport, fragmentation, and the outbursts exemplified by FU Ori and EX Lupi systems. The outer ...

  • Instabilities and transport in magnetized plasmas 

    Rosin, Mark (University of CambridgeDepartment of Applied Mathematics and Theoretical PhysicsDarwin College, 2011-02-08)
    In a magnetized plasma, naturally occurring pressure anisotropies facilitate in- stabilities that are expected to modify the transport properties of the system. In this thesis we examine two such instabilities and, where ...

  • MRI turbulence and thermal instability in accretion discs 

    Ross, J; Latter, Henrik Nils; Tehranchi, Michael Rummine (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2017-06)
    A long-standing puzzle in the study of black hole accretion concerns the presence or not of thermal instability. Classical theory predicts that the encircling accretion disc is unstable, as do some self-consistent ...

  • On the nature of the magnetic Rayleigh–Taylor instability in astrophysical plasma: the case of uniform magnetic field strength 

    Hillier, Andrew S. (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-07-28)
    The magnetic Rayleigh–Taylor instability has been shown to play a key role in many astrophysical systems. The equation for the growth rate of this instability in the incompressible limit, and the most-unstable mode that ...

  • On turbulence driven by axial precession and tidal evolution of the spin–orbit angle of close-in giant planets 

    Barker, Adrian J. (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-05-16)
    The spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. This induces internal fluid ...

  • Quasi-cyclic behaviour in non-linear simulations of the shear dynamo 

    Teed, Robert John; Proctor, Michael Richard (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2017-02-17)
    The solar magnetic field displays features on a wide range of length-scales including spatial and temporal coherence on scales considerably larger than the chaotic convection that generates the field. Explaining how the ...

  • Quasi-periodic oscillations and the global modes of relativistic, MHD accretion discs 

    Dewberry, Janosz W; Latter, Henrik Nils; Ogilvie, Gordon Ian
    The high-frequency quasi-periodic oscillations (HFQPOs) that punctuate the light curves of X-ray binary systems present a window onto the intrinsic properties of stellar-mass black holes and hence a testbed for general ...

  • The stress–pressure relationship in simulations of MRI-induced turbulence 

    Ross, Johnathan; Latter, Henrik Nils; Guilet, Jerome (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2016-01-01)
    We determine how MRI (magnetorotational instability)-turbulent stresses depend on gas pressure via a suite of unstratified shearing box simulations. Earlier numerical work reported only a very weak dependence at best, ...

  • Torsional Alfvén resonances as an efficient damping mechanism for non-radial oscillations in red giant stars 

    Loi, ST; Papaloizou, John Christopher (Oxford University PressMonthly Notices of the Royal Astronomical Society, 2017-06-01)
    Stars are self-gravitating fluids in which pressure, buoyancy, rotation and magnetic fields provide the restoring forces for global modes of oscillation. Pressure and buoyancy energetically dominate, while rotation and ...