Effects of parallel ion motion on electromagnetic toroidal ion temperature gradient modes in a fluid model

Artikel i vetenskaplig tidskrift, 2015

Effects of ion dynamics along the background magnetic field have been added to an advanced fluid model which has been developed, tested, and successfully used in transport code applications during the last decades. Introducing electrostatic ($\phi$) and electromagnetic potentials ($\psi$), a system of two coupled second order differential equations in these potentials is derived. The mode solution is interpreted as a coupling between an Ion Temperature Gradient (ITG) mode and an ion motion driven acoustic wave. The mode may be stabilized by electromagnetic effects and by minimizing the ITG parameter ($\eta_i = L_n/L_{Ti}$). Interestingly, the addition of kinetic Landau resonance effects may enhance the $\eta_i$ stabilization.