Effect of rotating liquid samples on dynamic propagation and aqueous activation of a helium plasma jet

This paper aims to explore the effects of a rotating plasma-activated liquid on the dynamic propagation and biomedical application of a helium plasma jet. The spatial distribution of reactive species and the associated physico-chemical reactions are altered by the rotating liquid, which shows a significant weakening in the axial propagation of the plasma bullet and a strengthening in its radial expansion at the liquid surface. The phenomenon is prompted by the nonzero rotational velocity of the liquid and is regulated by airflow, target distance and liquid permittivity. The concentrations of aqueous reactive species, especially OH and ${\mathrm{O}}_2^{-},$ and the inactivation effectiveness on cancer cells are weakened, indicating that a rotating liquid is not conducive to water treatment of the plasma jet although the treatment area of the plasma jet increases dynamically. This finding is of significance for the plasma–liquid interaction and the biomedical-related applications of plasma jets.