Theoretical AC susceptibility of superconducting multifilamentary tapes in a perpendicular field

We study theoretically the AC susceptibility of hard type-II superconducting multifilamentary tape when placed in a perpendicular AC magnetic field. We focus on three different arrangements of identical filaments of rectangular cross-section: three filaments stacked in the applied field direction (vertical array), three filaments aligned in the field perpendicular direction (horizontal array), and the case of a 3*3 filament matrix. Real and imaginary AC susceptibility are calculated within the critical state framework. For the geometries of horizontal array and matrix are studied the cases whether the critical current returns inside each filament or it returns to the other filament placed symmetrically in the horizontal direction.