A study of parallel viscosity, convection and particle flux in a TOKAMAK plasma

Nuclear fusion is considered to be a relatively environmentally friendly energy source with unexhaustible fuel resources. However, to exploit the reaction, high technology is required. One of the main problems in nuclear fusion is plasma confiment and thus the study of transport processes is of interest. In this work, Monte Carlo guiding center orbit following code ASCOT is used for calculations of the radial particle fluxes, parallel and poloidal viscosities, and convective momentum transport for ions in a poloidally rotating tokamak plasma, including a large mass flow velocity without imposing the usual constraint that VpB/(vtiBp) be small. Here, Vp is the poloidal plasma flow velocity, vti is the ion thermal speed. B is the magnetic field, and Bp is the poloidal magnetic field strength. Collisions are calculated with a binary collision method to conserve momentum and energy pairwise in collisions, and to include the poloidal nonuniformities in the collision operator. This operator is compared with the test particle collision model. The radial electric field is obtained from the polarisation equation or is assumed to be sustained by an external current or torque. The poloidal electric field is determined from the Maxwell-Boltzmann law. The accuracy of the method and its numerical implementation are described in detail in the presentation (author)