scholarly journals Transport Coefficients of the Second Order Hydrodynamics and the Applicability of Hydrodynamic Model

2012 ◽  
Vol 193 ◽  
pp. 327-330
Author(s):  
Shin Muroya
Keyword(s):  
Hydrodynamic Model ◽  
Transport Coefficients ◽  
Second Order

scholarly journals Lattice study of transport coefficients in second order dissipative hydrodynamics

2011 ◽  
Author(s):  
Y. Kohno ◽  
Masayuki Asakawa ◽  
Masakiyo Kitazawa ◽  
Chiho Nonaka
Keyword(s):  
Transport Coefficients ◽  
Second Order

scholarly journals PRODUCTION OF THERMAL PHOTONS IN A SIMPLE CHIRAL-HYDRODYNAMIC MODEL

2012 ◽  
Vol 18 ◽  
pp. 216-220
Author(s):  
J. PERALTA-RAMOS ◽  
M. S. NAKWACKI
Keyword(s):  
Boltzmann Equation ◽  
Equation Of State ◽  
Shear Viscosity ◽  
Hydrodynamic Model ◽  
Order Theory ◽  
Second Order ◽  
Temperature Dependent ◽  
Dissipative Effects ◽  
Linearized Boltzmann Equation ◽  
Self Consistent

We use a self-consistent chiral-hydrodynamic formalism which combines the linear σ model with second-order hydrodynamics in 2 + 1 dimensions to compute the spectrum of thermal photons produced in Au+Au collisions at [Formula: see text]. The temperature-dependent shear viscosity of the model, η, is calculated from the linearized Boltzmann equation. We compare the results obtained in the chiral-hydrodynamic model to those obtained in the second-order theory with a Lattice QCD equation of state and a temperature-independent value of η/s. We find that the thermal photon production is significantly larger in the latter model due to a slower evolution and larger dissipative effects.

scholarly journals Cosmic ray momentum diffusion in the presence of nonlinear Alfvén waves

1996 ◽  
Vol 3 (1) ◽  
pp. 66-76 ◽  
Author(s):  
G. Michałek ◽  
M. Ostrowsky
Keyword(s):  
Diffusion Coefficient ◽  
Shock Waves ◽  
Wave Field ◽  
Transport Coefficients ◽  
Cosmic Ray ◽  
High Amplitude ◽  
Second Order ◽  
Fermi Acceleration ◽  
Large Wave ◽  
Wave Fields

Abstract. The relation between the spatial diffusion coefficient along the magnetic field, kII, and the momentum diffusion coefficient, Dp, for relativistic cosmic ray particles is modelled using Monte Carlo simulations. Wave fields with vanishing wave helicity and cross-helicity, constructed by superposing 'Alfvén-like' waves are considered. As the result, particle trajectories in high amplitude wave fields and then - by averaging over these trajectories - the values of transport coefficients are derived. The modelling is performed at various wave amplitudes, from δ B/B0 = 0.15 to 2.0, and for a number of wave field types. At our small amplitudes approximately the quasi-linear theory (QLT) estimates for kII and Dp are reproduced. However, with growing wave amplitude the simulated results show a small divergence from the QLT ones, with kII decreasing slower than theoretical prediction and the opposite being true for Dp. The wave field form gives only a slight influence on the wave-particle interactions at large wave amplitudes δ B/B0 ~ 1. The parameter characterizing the relative efficiency of the second-order to the first-order acceleration at shock waves, Dp κII is given in the QLT approximation by the Skilling formula V2A p2 / 9. In simulations together with increasing δ B it increases above this scale in all the cases under our study. Consequences of the present results for the second-order Fermi acceleration at shock waves are briefly addressed.

scholarly journals Relativistic non-resistive viscous magnetohydrodynamics from the kinetic theory: a relaxation time approach

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Ankit Kumar Panda ◽  
Ashutosh Dash ◽  
Rajesh Biswas ◽  
Victor Roy
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Transport Coefficients ◽  
Second Order ◽  
Navier Stokes ◽  
Relaxation Time Approximation ◽  
Moment Approximation ◽  
System Of Particles ◽  
Anisotropic Transport ◽  
The Magnetic Field

Abstract We derive the relativistic non-resistive, viscous second-order magnetohydrodynamic equations for the dissipative quantities using the relaxation time approximation. The Boltzmann equation is solved for a system of particles and antiparticles using Chapman-Enskog like gradient expansion of the single-particle distribution function truncated at second order. In the first order, the transport coefficients are independent of the magnetic field. In the second-order, new transport coefficients that couple magnetic field and the dissipative quantities appear which are different from those obtained in the 14-moment approximation [1] in the presence of a magnetic field. However, in the limit of the weak magnetic field, the form of these equations are identical to the 14-moment approximation albeit with different values of these coefficients. We also derive the anisotropic transport coefficients in the Navier-Stokes limit.

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