Synthetic Phase Contrast Imaging at the Wendelstein 7-X Stellarator*

As the largest neoclassically optimized stellarator, Wendelstein 7-X (W7-X) plays a crucial role in stellarator turbulence studies. The main core turbulence diagnostic at W7-X is the phase contrast imaging (PCI) system, which measures the line-integrated fluctuating electron density along a central line-of-sight. The line-integrated nature of the PCI measurements complicates the interpretation of experimental data. It is thus advantageous to utilize synthetic PCI diagnostics, capable of computing the expected PCI signal based on model electron density fluctuations. This contribution describes results obtained with such a synthetic diagnostic at W7-X, including input from the first nonlinear, global gyrokinetic simulations of stellarators with kinetic electrons.