Divergence in the Density Expansion of the Transport Coefficients of a Two-Dimensional Gas

1966 ◽  
Vol 9 (9) ◽  
pp. 1685 ◽  
Author(s):  
J. V. Sengers
Keyword(s):  
Transport Coefficients ◽  
Two Dimensional ◽  
Density Expansion

scholarly journals Proton temperature-anisotropy-driven instabilities in weakly collisional plasmas: Hybrid simulations

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Petr Hellinger ◽  
Pavel M. Trávníček
Keyword(s):  
Magnetic Field ◽  
Langevin Equation ◽  
Transport Coefficients ◽  
Two Dimensional ◽  
Temperature Anisotropy ◽  
Coulomb Collisions ◽  
Proton Temperature ◽  
Collisionless Plasmas ◽  
High Beta ◽  
Kinetic Instabilities

Kinetic instabilities in weakly collisional, high beta plasmas are investigated using two-dimensional hybrid expanding box simulations with Coulomb collisions modeled through the Langevin equation (corresponding to the Fokker-Planck one). The expansion drives a parallel or perpendicular temperature anisotropy (depending on the orientation of the ambient magnetic field). For the chosen parameters the Coulomb collisions are important with respect to the driver but are not strong enough to keep the system stable with respect to instabilities driven by the proton temperature anisotropy. In the case of the parallel temperature anisotropy the dominant oblique fire hose instability efficiently reduces the anisotropy in a quasilinear manner. In the case of the perpendicular temperature anisotropy the dominant mirror instability generates coherent compressive structures which scatter protons and reduce the temperature anisotropy. For both the cases the instabilities generate temporarily enough wave energy so that the corresponding (anomalous) transport coefficients dominate over the collisional ones and their properties are similar to those in collisionless plasmas.

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