Collisions in magnetised plasmas (Q2786516)

A complete survey of collisions and collision operators is offered here, which are useful in the description of magnetized plasmas mainly used in the preparation of ITER experiments (fusion research). The main purpose is the foundation of special simulations of turbulent transport phenomena in order to understand and monitor the confinement performance of the device in question. In the case of ITER, the plasma is characterised by a very small collisionality, since the typical distance between the particles ranges from \(10^{-6}\) m to \(10^{-7}\) m, so in this case the weak binary collisions prevail. This range of interparticle distance allows the use of the classical collision picture to derive the analytical conception in the formulation of collision operators. An important step is that instead of the BBGKY expansion, an averaging procedure is proposed by differentiating the various states to determine a state probability that is assumed to be continuous. The derivation of the Landau collision operator is introduced through a quasilinear approach to calculate the correlation function of the fluctuating distribution of the interacting particles. This leads to an elegant formalism.NEWLINENEWLINEFrom this, the Lenard-Balescu collision operator is straightforwardly obtained, and the expansion of the correlation function and the propagator formalism are shown. Here a simple renormalisation scheme is introduced to sum up the contributions that appear in an expansion of the plasma permitivity. The distribution function gradients at the Debye scale are obtained together with the collision operator for magnetized plasma in this approximation. The conservation laws and the entropy production (due to the collision operator) are formulated.