Fokker–Planck and non-linear hydrodynamic equations of an inelastic system of several Brownian particles in a non-equilibrium bath

1998 ◽  
Vol 250 (1-4) ◽  
pp. 265-294 ◽  
Author(s):  
Joan-Emma Shea ◽  
Irwin Oppenheim
Keyword(s):  
Hydrodynamic Equations ◽  
Brownian Particles ◽  
Non Linear ◽  
Non Equilibrium ◽  
Fokker Planck

scholarly journals Non-Linear Langevin and Fractional Fokker–Planck Equations for Anomalous Diffusion by Lévy Stable Processes

Entropy ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 760 ◽  
Author(s):  
Johan Anderson ◽  
Sara Moradi ◽  
Tariq Rafiq
Keyword(s):  
Anomalous Diffusion ◽  
Transport Coefficient ◽  
Numerical Solutions ◽  
Distribution Functions ◽  
Space Distribution ◽  
Non Linear ◽  
Non Local ◽  
Local Transport ◽  
Fokker Planck Equations ◽  
Fokker Planck

The numerical solutions to a non-linear Fractional Fokker–Planck (FFP) equation are studied estimating the generalized diffusion coefficients. The aim is to model anomalous diffusion using an FFP description with fractional velocity derivatives and Langevin dynamics where Lévy fluctuations are introduced to model the effect of non-local transport due to fractional diffusion in velocity space. Distribution functions are found using numerical means for varying degrees of fractionality of the stable Lévy distribution as solutions to the FFP equation. The statistical properties of the distribution functions are assessed by a generalized normalized expectation measure and entropy and modified transport coefficient. The transport coefficient significantly increases with decreasing fractality which is corroborated by analysis of experimental data.

scholarly journals Kelvin-Helmholtz Instabilities and the Emission Knots in Herbig-Haro Jets

1997 ◽  
Vol 182 ◽  
pp. 335-342 ◽  
Author(s):  
S. Massaglia ◽  
M. Micono ◽  
A. Ferrari ◽  
G. Bodo ◽  
P. Rossi
Keyword(s):  
Numerical Simulations ◽  
Astrophysical Jets ◽  
General Applicability ◽  
Simple Assumption ◽  
Linear Evolution ◽  
Radiation Losses ◽  
Non Linear ◽  
Constant Heating ◽  
Non Equilibrium

We discuss the non-linear evolution of Kelvin-Helmholtz instabilities in Herbig-Haro jets performing numerical simulations by means of a PPM hydro-code modified as to include non-equilibrium, optically thin, radiation losses and heating. In this paper we discuss in particular the effects of different functional dependences of heating on density. The results obtained show a weak dependency of the instability evolution on the different forms of the heating function, that is largely unknown, therefore the simple assumption of constant heating, adopted in previous papers on this matter, does not lead to severe limitations on the general applicability of the results to the astrophysical jets and, in particular, to the origin of the emission knots.

scholarly journals Non-equilibrium parameter for a hybrid Fokker-Planck/DSMC scheme

2019 ◽  
Author(s):  
Christian Hepp ◽  
Martin Grabe ◽  
Klaus Hannemann
Keyword(s):  
Equilibrium Parameter ◽  
Non Equilibrium ◽  
Fokker Planck
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