1 EX / 4-5 Confinement in Wendelstein 7X Limiter Plasmas

Observations on confinement in the first experimental campaign on the optimized Stellarator Wendelstein 7-X are summarized. In this phase W7-X was equipped with five inboard limiters only and thus the discharge length restricted to avoid local overheating. Stationary plasmas are limited to low densities < 2 to 3 · 10 m. With the available 4.3 MW ECR heating core Te~ 8 keV, Ti ~ 1 to 2 keV are achieved routinely resulting in energy confinement time E between 100 to 150ms. For these conditions the plasmas show characteristics of core electron root confinement with peaked Te-profiles and positive Er up to about half of the minor radius. Profiles and plasma currents respond to onand off-axis heating and coand counter ECCD respectively.