Simulations of the Formation of a Transport Barrier in Four Channels Including Turbulent Poloidal Momentum, Spin up
We have simulated the formation of a transport barrier on JET including a self-consistent treatment of ion and electron temperatures and poloidal and toroidal momentum. This has included an anomalous spinup of poloidal momentum similar to that in the experiment. We have used either the experimental profiles, with transport barrier, or artificial initial profiles, without barrier, as initial condition. The experimental density (with no barrier) was used and kept fixed . The result was that barriers, or spinup, developed in all channels with profiles close to the experimental. Note that there is no free parameter in the code but the uncertainty in Zeff has been used for adjustments.The barrier developes at a region with small magnetic shear outside the main deposition of energy. The physics of the poloidal spinup was the development of zonal flows. For the toroidal momentum pinch the symmetry breaking effect of toroidicity was dominant.