SUPPRESSION OF COHERENT STRUCTURES IN SHEARED PLASMA FLOWS

Numerical simulations of vortical structures in 2D electrostatic plasm as in an annular geometry show that by varying the boundary conditions it is possible to suppress vortices of one polarity, thereby eliminat ing propagating dipolar structures. Transport of plasma caused by prop agating dipolar structures is consequently reduced, or even eliminated , by the externally imposed electric field. The results have implicati ons for understanding cross-field transport of plasmas in the presence of coherent structures.