Negative superdiffusion due to the inhomogeneous convection

TL;DR

This paper investigates fractional particle transport on a comb structure with inhomogeneous convection, revealing a novel superdiffusive spread opposite to the flow direction under certain conditions.

Contribution

It introduces the phenomenon of negative superdiffusion caused by inhomogeneous convection in fractional transport models on comb structures.

Findings

Contaminant spreads superdiffusively opposite to convection flow.

Conditions for negative superdiffusion are detailed.

Large scale asymptotics are used to analyze the effect.

Abstract

Fractional transport of particles on a comb structure in the presence of an inhomogeneous convection flow is studied. The large scale asymptotics is considered. It is shown that a contaminant spreads superdiffusively in the direction opposite to the convection flow. Conditions for the realization of this new effect is discussed in detail.