49 research outputs found
State-to-State Kinetic Theory Approach for Transport and Relaxation Processes in Viscous Reacting Gas Flows
Abstract. In the paper, the description of non-equilibrium reacting gas flows taking into account detailed vibrational and chemical kinetics is considered on the basis of the kinetic theory methods. The kinetic models for transport and relaxation processes are presented, and peculiar features of transport coefficients in the state-to-state approach for reacting flows are demonstrated. Contribution of different dissipative processes to the diffusion velocity and heat flux is discussed. The statedependent rate coefficients for vibrational energy transitions, dissociation, recombination and exchange chemical reactions are studied in the zero-and first-order approximations of modified Chapman-Enskog method. Practical applications of proposed models for non-equilibrium gas-dynamics problems are discussed
State-to-State Kinetic Theory Approach for Transport and Relaxation Processes in Viscous Reacting Gas Flows
Abstract. In the paper, the description of non-equilibrium reacting gas flows taking into account detailed vibrational and chemical kinetics is considered on the basis of the kinetic theory methods. The kinetic models for transport and relaxation processes are presented, and peculiar features of transport coefficients in the state-to-state approach for reacting flows are demonstrated. Contribution of different dissipative processes to the diffusion velocity and heat flux is discussed. The statedependent rate coefficients for vibrational energy transitions, dissociation, recombination and exchange chemical reactions are studied in the zero-and first-order approximations of modified Chapman-Enskog method. Practical applications of proposed models for non-equilibrium gas-dynamics problems are discussed
Plasma kinetics issues in an ESA study for a plasma laboratory in space
A study supported by the European Space Agency (ESA), in the context of its General Studies Programme, performed an investigation of the possible use of space for studies in pure and applied plasma physics, in areas not traditionally
covered by ‘space plasma physics’. A set of experiments have been identified that can potentially provide access to new phenomena and to allow advances in several fields of plasma science. These experiments concern phenomena on a
spatial scale (101–104 m) intermediate between what is achievable on the ground and the usual solar system plasma observations. Detailed feasibility studies have been performed for three experiments: active magnetic experiments, largescale discharges and long tether–plasma interactions. The perspectives opened by these experiments are discussed for magnetic reconnection, instabilities,
MHD turbulence, atomic excited states kinetics, weakly ionized plasmas,plasma diagnostics, artificial auroras and atmospheric studies. The discussion is also supported by results of numerical simulations and estimates
The ESA "Plasma Laboratory in Space" study
The European Space Agency has initiated, in the context of its General Studies Programme, a study of the
possible use of space for studies in pure and applied plasma physics, in areas not traditionally covered by “space plasma physics”. A team of experts has been set-up to review a broad range of area including industrial
plasma physics and pure plasma physics, astrophysical and solar-terrestrial areas. A set of experiments have been identified that can potentially provide access to new phenomena and to allow advances in several fields
of plasma science. These experiments concern phenomena on spatial scale (102 to104 m) intermediate between what is achievable on ground experiment and usual solar system plasma observations
Kinetic Theory of Plasmas: Translational Energy
In the present contribution, we derive from kinetic theory a unified fluid
model for multicomponent plasmas by accounting for the electromagnetic field
influence. We deal with a possible thermal nonequilibrium of the translational
energy of the particles, neglecting their internal energy and the reactive
collisions. Given the strong disparity of mass between the electrons and heavy
particles, such as molecules, atoms, and ions, we conduct a dimensional
analysis of the Boltzmann equation. We then generalize the Chapman-Enskog
method, emphasizing the role of a multiscale perturbation parameter on the
collisional operator, the streaming operator, and the collisional invariants of
the Boltzmann equation. The system is examined at successive orders of
approximation, each of which corresponding to a physical time scale. The
multicomponent Navier-Stokes regime is reached for the heavy particles, which
follow a hyperbolic scaling, and is coupled to first order drift-diffusion
equations for the electrons, which follow a parabolic scaling. The transport
coefficients exhibit an anisotropic behavior when the magnetic field is strong
enough. We also give a complete description of the Kolesnikov effect, i.e., the
crossed contributions to the mass and energy transport fluxes coupling the
electrons and heavy particles. Finally, the first and second principles of
thermodynamics are proved to be satisfied by deriving a total energy equation
and an entropy equation. Moreover, the system of equations is shown to be
conservative and the purely convective system hyperbolic, thus leading to a
well-defined structure
Effective-Range Expansion of the Neutron-Deuteron Scattering Studied by a Quark-Model Nonlocal Gaussian Potential
The S-wave effective range parameters of the neutron-deuteron (nd) scattering
are derived in the Faddeev formalism, using a nonlocal Gaussian potential based
on the quark-model baryon-baryon interaction fss2. The spin-doublet low-energy
eigenphase shift is sufficiently attractive to reproduce predictions by the
AV18 plus Urbana three-nucleon force, yielding the observed value of the
doublet scattering length and the correct differential cross sections below the
deuteron breakup threshold. This conclusion is consistent with the previous
result for the triton binding energy, which is nearly reproduced by fss2
without reinforcing it with the three-nucleon force.Comment: 21 pages, 6 figures and 6 tables, submitted to Prog. Theor. Phy