Fig. 11

Simplified model of parallel Poynting flux in vicinity of a plasma depletion. a Elliptical conductance depletion in plane perpendicular to the geomagnetic field. The plane perpendicular to B has a horizontal coordinate that runs magnetic east-west and vertical coordinate that is normal to the horizontal coordinate and to B. The scaling is arbitrary but determines the magnitudes of the fields. a–c are universal and do not depend on the hemisphere. Darker tones represent deeper depletion. The scaling is arbitrary. b Equipotential contours and electric field vectors representing the polarization of the depletion due to an eastern background current. Light (dark) tones represent positive (negative) potential. c Field-aligned current density antiproportional to the transverse Laplacian of the potential. Light (dark) tones represent poleward (equatorward) current density. d Magnetic field perturbations caused by the current density in c in the northern hemisphere. e Magnetic field perturbation caused by the interruption of the background northward field-aligned current density in the northern hemisphere. f Poynting flux perturbation in the northern hemisphere associated with a linear combination of d and e. Light (dark) tones represent positive (negative) perturbations in the northward flux