Dimensionless scaling laws of confinement in fusion plasmas with the 5D non-linear GYrokinetic SEmi-LAgrangian code (GYSELA)

This work addresses non-linear global gyrokinetic simulations of ITG turbulence in a simple toroidal geometry with the GYSELA code. This code solves the gyrokinetic equation for ions, coupled to a quasi-electroneutrality condition. The electron response is assumed adiabatic. The particularity of GYSELA code is to solve the Vlasov-Poisson like system on a fixed grid with a Semi-Lagrangian (SL) scheme $[1]$ for the entire distribution function. The 4D non-linear drift-kinetic version of the code has already shown the interest of such a SL method $[2]$. The energy conservation, which is recognized as a key test of validity, was achieved with an accuracy better than $2.5\%$. Results with the new 5D version of GYSELA will be presented, in particular a scan of turbulent transport for several values of the normalized gyroradius $\rho$star. The aim is to determine the dimensionless scaling law of confinement and to compare it with previous studies in this field $[3]$-$[4]$.\vspace{10pt}\\ $[1]$ E. Sonnendr\"{u}cker et al, Journal of Comput. Physics, 149, 201-220, 1999.\\ $[2]$ V. Grandgirard et al, accepted in Journal of Comput. Physics.\\ $[3]$ J. Candy and R.E. Waltz, Phys. Rev. Lett. 91, 2003.\\ $[4]$ Z. Lin et al., Phys. Rev. Lett. 82, 2002.\\