title: Blob dynamics in 3D BOUT simulations of tokamak edge turbulence.
abstract: Propagating filaments of enhanced plasma density, or blobs, observed in 3D numerical simulations of a diverted, neutral-fueled tokamak are studied. Fluctuations of vorticity, electrical potential phi, temperature Te, and current density J parallel associated with the blobs have a dipole structure perpendicular to the magnetic field and propagate radially with large E x B drift velocities (>1 km/s). The simulation results are consistent with a 3D blob dynamics model that incorporates increased parallel plasma resistivity (from neutral cooling of the X-point region), blob disconnection from the divertor sheath, X-point closure of the current loops, and collisional physics to sustain the phi, Te, J parallel dipoles.
authors.affiliation: Lodestar Research Corporation, Boulder, Colorado 80301, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Russell
authors.forename: D A
authors.initials: DA
authors.lastname: D'Ippolito
authors.forename: J R
authors.initials: JR
authors.lastname: Myra
authors.forename: W M
authors.initials: WM
authors.lastname: Nevins
authors.forename: X Q
authors.initials: XQ
authors.lastname: Xu