Research Commons

Browsing Computing and Mathematical Sciences Papers by Submit Date

Research Commons

Browsing Computing and Mathematical Sciences Papers by Submit Date

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  • Oughton, Sean (American Institute of Physics, 2003)
    We present a brief review of observations and theory regarding the nature and radial evolution of MHD‐scale solar wind fluctuations. Emphasis is placed on the fact that the fluctuations consist of both waves and turbulence, ...
  • Milano, L. J.,; Matthaeus, William H.; Dmitruk, Pablo; Oughton, Sean (American Institute of Physics, 2003)
    In the presence of a weakly inhomogeneous background, magnetohydrodynamic fluctuations are transported, reflected and at small scales, dissipated. In contrast to orderings appropriate to outer solar wind conditions, here ...
  • Oughton, Sean (Cambridge University Press, 1996)
    We report on results from direct numerical simulation of the incompressible three- dimensional magnetohydrodynamic (MHD) equations, modified to incorporate viscous dissipation via the strongly anisotropic ion-parallel ...
  • Matthaeus, William H.; Zank, Gary P.; Oughton, Sean (1996)
    A simple phenomenology is developed for the decay and transport of turbulence in a constant-speed, uniformly expanding medium. The fluctuations are assumed to be locally incompressible, and either of the hydrodynamic or ...
  • Matthaeus, William H.; Oughton, Sean; Pontius, Duane H.; Zhou, Ye (1995)
    In their preceding comment on our paper [Matthaeus et al., 1994] (hereinafter reffered to as paper 1), Tu and Marsh [this issue] object vehemently to what they perceive as undeserved criticism of the class of solar wind ...
  • Oughton, Sean (Cambridge University Press, 1997)
    Analytic results for the time dependences of the kinetic and magnetic energies of an incompressible magneto fluid threaded by a strong uniform magnetic field B₀ are obtained. The governing equations are the linearised ...
  • Matthaeus, William H.; Mullan, D. J.; Dmitruk, Pablo; Milano, L. J.; Oughton, Sean (2003)
    This paper discusses the possibility that heating of the solar corona in open field-line regions emanating from coronal holes is due to a nonlinear cascade, driven by low-frequency or quasi-static magnetohydrodynamic ...
  • Matthaeus, William H.; Stribling, W.; Martinez, Daniel; Oughton, Sean; Montgomery, David (American Physical Society, 1991)
    Numerical solution of two-dimensional incompressible hydrodynamics shows that states of a near-minimal ratio of enstrophy to energy can be attained in times short compared with the flow decay time, confirming the simplest ...
  • Zank, Gary P.; Oughton, Sean (1991)
    The one-dimensional hydrodynamics of flows subjected to mass loading are considered anew, with particular emphasis placed on determining the properties of mass-loading shocks. This work has been motivated by recent ...
  • Zank, Gary P.; Oughton, Sean; Neubauer, F. M.; Webb, G. M. (1991)
    Recent observations at comets Giacobini-Zinner and Halley suggest that simple non-reacting gas dynamics or MHD is an inappropriate description for the bow shock. The thickness of the observed (sub)shock implies that ...
  • Montgomery, David; Matthaeus, William H.; Stribling, W. T.; Martinez, D.; Oughton, Sean (American Institute of Physics, 1992)
  • Zank, Gary P.; Oughton, Sean; Neubauer, F. M.; Webb, G. M. (1992)
    The one-dimensional magnetohydrodynamics of shocked flows subjected to significant mass loading are considered. Recent observations at comets Giacobini-Zinner and Halley suggest that simple nonreacting MHD is an inappropriate ...
  • Matthaeus, William H.; Zhou, Ye; Zank, Gary P.; Oughton, Sean (1994)
    An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow with a ...
  • Oughton, Sean; Priest, Eric R.; Matthaeus, William H. (Cambridge University Press, 1994)
    Building on results from two-dimensional magnetohydrodynamic (MHD) turbulence (Shebalin, Matthaeus & Montgomery 1983), the development of anisotropic states from initially isotropic ones is investigated numerically for ...
  • Matthaeus, William H.; Oughton, Sean; Pontius, Duane H.; Zhou, Ye (1994)
    Previous theoretical treatments of fluid-scale turbulence in the solar wind have concentrated on describing the state and dynamical evolution of fluctuations in the inertial range, which are characterized by power law ...
  • Hossain, Murshed; Gray, Perry C.; Pontius, Duane H.; Matthaeus, William H.; Oughton, Sean (American Institute of Physics, 1995)
    We evaluate a number of simple, one‐point phenomenological models for the decay of energy‐containing eddies in magnetohydrodynamic(MHD) and hydrodynamicturbulence. The MHDmodels include effects of cross helicity and Alfvénic ...
  • Stribling, Troy; Matthaeus, William H.; Oughton, Sean (American Institute of Physics, 1995)
    A computational investigation of magnetic helicity of the fluctuatingmagnetic fieldHm in ideal and freely decaying three‐dimensional (3‐D) magnetohydrodynamics (MHD) in the presence of a uniform mean magnetic field is ...
  • Oughton, Sean; Matthaeus, William H. (1995)
    Numerical solutions for the linear transport of solar wind fluctuations are presented. The model used takes into account the effects of advection, expansion, and wave propagation, as well as the recently illuminated effects ...
  • Matthaeus, William H.; Ghosh, Sanjoy; Oughton, Sean; Roberts, D. Aaron (1996)
    Direct spectral method simulation of the three-dimensional magnetohydrodynamics (MHD) equations is used to explore anisotropy that develops from initially isotropic fluctuations as a consequence of a uniform applied magnetic ...
  • Oughton, Sean; Rädler, K.-H.; Matthaeus, William H. (The American Physical Society, 1997)
    The properties and structure of second-order (Cartesian) correlation tensors are derived for the general case of two solenoidal random vector fields. The theory is intended to describe homogeneous magnetohydrodynamic ...