UC San Diego

Plasma blobs (filamentary structures extended along the magnetic field lines) are mesoscale turbulent structures that are usually observed in the scrape-off layer (SOL) of magnetic confinement devices. Electromagnetic fluid simulations for seeded high-beta blobs demonstrate that inhomogeneity of magnetic curvature or plasma pressure along the filament leads to bending of the filaments and magnetic field lines due to increased Alfven time. Moreover, the drift wave instabilities inside the filaments are modified by electromagnetic effects. A local linear analysis on an electromagnetic drift-kinetic equation with BGK-like collision operator proves to be valid for describing the linear growth rate of drift wave instabilities in a wide range of plasma parameters showing convergence to reference models for limiting cases. Finally, the development of the 5D version of the full-f gyrokinetic code COGENT and its application to the collisionless drift wave simulation are presented with discussion of the disturbance of the distribution function from the collisionless drift wave instability and the formation of a helical mode structure within the plasma filament.