Scalings and Plasma Profile Parameterisation of ASDEX High Density Ohmic Discharges

Abstract

High density ($.3 < \bar{n}/10^{20}{\rm m^{-3}} < .8$), low $q_a$ ($1.9<q_a<3.4$), Ohmic discharges from the ASDEX experiment is analysed statistically. Bulk parameter scalings and parameterised temperature and density profile shapes are presented. The total plasma kinetic energy, assuming $T_i=T_e$, scales as $\bar{n}^{\ .54\pm .01} {I_p}^{.90\pm .04 } $ and is almost independent of $B_t$. The electron temperature profile peaking factor scales as ${T_0^{3/2}/<T^{3/2}>} = .94(\pm.04){q_a}^{1.07\pm.04}$ in close agreement with the assumption of classical resistive equilibrium. In the inner half of the plasma, the inverse fall-off length for both temperature and density has a strong dependence on $q_a$, with the temperature dependence being more pronounced. Outside the half radius, the $q_a$ dependence disappears but the density profile broadens near the edge with increasing plasma current.