The radialmotion of isolated filamentary structures inmagnetized plasmas strongly depends on both the level of collisional dissipation and the parallel dynamics. In weakly ionized plasmas, such as the ionosphere and basic laboratory experiments, the motion of localized plasma blobs or depletions is influenced by the collisional friction with the neutral gas fluid. In magnetically confined plasmas, the motion of filamentary structures in the edge region can be influenced by parallel dynamics in a manner that resembles an effective friction. In the presence of strong ballooning, such a frictional response may take place in both the electrostatic and the electromagnetic regimes. Results are presented from two-dimensional numerical simulations of an isolated blob structure in a non-uniform magnetic field [1,2]. The effect of a linear damping term in the vorticity equation, which describes an effective friction, is investigated. In the inertial regime the radial filament velocity scales as the square root of its size. In the limit of strong friction regime the velocity scales as the inverse of the structure size. A discussion of these results will be given in the context of irregularities in the equatorial ionosphere, field-aligned structures in simply magnetized torus configurations, and filamentary structures in magnetically confined plasmas.
|Publication status||Published - 2008|
|Event||13. EU-US TTF workshop 2008 and 1. EFDA Transport Topical Group meeting - Copenhagen (DK), 1-4 Sep|
Duration: 1 Jan 2008 → …
|Conference||13. EU-US TTF workshop 2008 and 1. EFDA Transport Topical Group meeting|
|City||Copenhagen (DK), 1-4 Sep|
|Period||01/01/2008 → …|
Garcia, O. E., Madsen, J., Naulin, V., Nielsen, A. H., & Juul Rasmussen, J. (2008). Effect of friction on the motion of plasma filaments. Paper presented at 13. EU-US TTF workshop 2008 and 1. EFDA Transport Topical Group meeting, Copenhagen (DK), 1-4 Sep, .