On the poloidal localization and stability of multi-faceted asymmetric radiation from the edge (MARFE)

A possible explanation for differences in the behavior of multi-faceted asymmetric radiation from the edge (MARFE) in normal and reversed toroidal field configurations, based on the influence of poloidal E×B drift, is offered. The poloidal E×B drift creates poloidal rotation that tends to shift the MARFE away from its stable position near the inner midplane. For a neoclassical radial electric field (Er≡−dΦ/dr<0), and in normal toroidal field configurations (ion ∇B drift towards the X-point), the E×B poloidal rotation shifts the MARFE towards another stable position, near the X-point. In the reversed toroidal field configurations (ion ∇B drift away from the X-point), the E×B poloidal rotation is shifting the MARFE away from the X-point. These trends are in agreement with experimental observations.