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A new formulation and simplified derivation of the dispersion function for a plasma with a kappa velocity distribution
Posted on July 20th, 2009 No commentsR. L. Mace and M. A. Hellberg<br/> A simplified derivation of the relationship between the dispersion function for a plasma with a kappa velocity distribution and the Gauss hypergeometric function is presented. This derivation relies on only a few standard integrals. It naturally leads to a new integral representation for the dispers … [Phys. Plasmas 16, 072113 (2009)] published Mon Jul 20, 2009.
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On reflection of solitary waves in a magnetized multicomponent plasma with nonisothermal electrons
Posted on July 20th, 2009 No commentsHitendra K. Malik, Dhananjay K. Singh, and Yasushi Nishida<br/> Reflection of ion acoustic solitary wave mechanicss is studied in a magnetized inhomogeneous multicomponent plasma with positive ions, negative ions, and two temperature nonisothermal electrons. Relevant modified Kortewegde Vries (mKdV) equations corresponding to two oppositely moving solitary wave mechanicss are coupl … [Phys. Plasmas 16, 072112 (2009)] published Mon Jul 20, 2009.
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Wave spectra of two-dimensional Yukawa solids and liquids in the presence of a magnetic field
Posted on July 20th, 2009 No commentsLu-Jing Hou, P. K. Shukla, Alexander Piel, and Z. L. Miskovic<br/> Thermally excited phonon spectra of two-dimensional Yukawa solids and liquids in the presence of an external magnetic field are studied using computer simulations. Special attention is paid to the variation of wave mechanics spectra in terms of several key parameters, such as the strength of coupling, the scr … [Phys. Plasmas 16, 073704 (2009)] published Mon Jul 20, 2009.
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On the dynamics of axisymmetric turbulent separating/reattaching flows
Posted on July 20th, 2009 No commentsPierre-Elie Weiss, Sebastien Deck, Jean-Christophe Robinet, and Pierre Sagaut<br/> The present work focuses on the intrinsic properties of an axisymmetric separating/reattaching flow. A numerical simulation of a compressible flow over a cylinder extended by another cylinder of smaller diameter is performed at a Reynolds number based on free stream velocity U and on the diameter of … [Phys. Fluids 21, 075103 (2009)] published Mon Jul 20, 2009.
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Resonance and propulsion performance of a heaving flexible wing
Posted on July 20th, 2009 No commentsSebastien Michelin and Stefan G. Llewellyn Smith<br/> The influence of the bending rigidity of a flexible heaving wing on its propulsive performance in a two-dimensional imposed parallel flow is investigated in the inviscid limit. Potential flow theory is used to describe the flow over the flapping wing. The vortical wake of the wing is accounted for b … [Phys. Fluids 21, 071902 (2009)] published Mon Jul 20, 2009.
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Relativistic dynamics of quasistable states. II. Differentiable representations of the causal Poincare semigroup
Posted on July 20th, 2009 No commentsS. Wickramasekara<br/> We construct two rigged Hilbert spaces that furnish differentiable representations of the causal Poincare semigroup. These rigged Hilbert spaces provide the mathematical foundation for a theory of relativistic quasistable states that synthesizes the S-matrix description of resonance scattering with … [J. Math. Phys. 50, 072302 (2009)] published Mon Jul 20, 2009.
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Noncommutative Kortewegde Vries and modified Kortewegde Vries hierarchies via recursion methods
Posted on July 20th, 2009 No commentsSandra Carillo and Cornelia Schiebold<br/> Here, noncommutative hierarchies of nonlinear equations are studied. They represent a generalization to the operator level of corresponding hierarchies of scalar equations, which can be obtained from the operator ones via a suitable projection. A key tool is the application of Backlund transformatio … [J. Math. Phys. 50, 073510 (2009)] published Mon Jul 20, 2009.
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Dual formulation of the Lie algebra S-expansion procedure
Posted on July 20th, 2009 No commentsF. Izaurieta, A. Perez, E. Rodriguez, and P. Salgado<br/> The expansion of a Lie algebra entails finding a new bigger algebra [fraktur G] through a series of well-defined steps from an original Lie algebra [fraktur g]. One incarnation of the method, the so-called S-expansion, involves the use of a finite Abelian semigroup S to accomplish this task. In this … [J. Math. Phys. 50, 073511 (2009)] published Mon Jul 20, 2009.
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Low-energy potential scattering in two and three dimensions
Posted on July 20th, 2009 No commentsN. N. Khuri, Andre Martin, J.-M. Richard, and Tai Tsun Wu<br/> Conditions are established for the existence of a scattering length and an effective range in the low-energy expansion of the S-wave mechanics phase shift of a central potential in two and three dimensions. The behavior of the phase shift as a function of the momentum is also derived for longer-range power-la … [J. Math. Phys. 50, 072105 (2009)] published Mon Jul 20, 2009.
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Nonlocal symmetries and integrable ordinary differential equations: x-double_dot +3xx-dot +x=0 and its generalizations
Posted on July 20th, 2009 No commentsA. Karasu (Kalkanli) and P. G. L. Leach<br/> The equation x-double_dot +3xx-dot +x=0 is well known in many areas of mathematics and physics theory. It possesses the algebra sl(3,R) of Lie point symmetries, hence is equivalent to the equation for a free particle, and both left and right Painleve series. We investigate two higher-dimensional analogs in … [J. Math. Phys. 50, 073509 (2009)] published Mon Jul 20, 2009.