Effect of random magnetic field on active-sterile neutrino conversion in the supernova core

The active-sterile neutrino conversion is studied for neutrino propagating in the axial potential generated by magnetised electron plasma in the supernova medium. We consider the effect of random magnetic field $B_{rms}$ on the average neutrino conversion probability. We obtained the constraint on $\Delta m^2$ and $\sin^2 2\theta$ for different strength of the random magnetic fields, by considering the positive definiteness of the average neutrino conversion probability inside the supernova core. Our calculation shows that, $B_{rms}\le 0.63\times 10^{14}$ Gauss is preferable so that small values of $\Delta m^2$ can not be excluded.