2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/97563A novel mechanism for the sign change of the Hall effect in the flux flow region is proposed. The difference $δn $ between the electron density at the center of the vortex core and that far outside the vortex causes the additional contribution to the Hall conductivity $δσ_{xy}=-δn ec/B$. This contribution can be larger than the conventional one in the dirty case $Δ(T)τ<1$. If the carrier density inside the core exceeds that far outside, a double sign change may occur as a function of temperature.12 pages Latex, no figures, submitted to PRLCondensed Mattertext