We quantify the impact of strong magnetic fields (assuming $B=B_0·r_0^3/r^3$ with $B_0\gtrsim {10}^{16}\mathrm{G}$) on the neutrino transport in core-collapse supernovae (CCSNe). Magnetic fields quantize the momenta of electrons and positrons, resulting in an enhanced absorption cross section for low-energy neutrinos and suppressed chemical potentials for $e^{\pm }$. We include these changes in the M1 scheme for neutrino transport and perform 1D CCSNe simulations with gr1d. The increased low-energy cross sections reduce the ${\overline{\nu }}_e$ mean energy $⟨E_{{\overline{\nu }}_e}⟩$ while elevating the neutrino number luminosities ${\mathcal{L}}_{\nu }$ for both ${\nu }_e$ and ${\overline{\nu }}_e$ due to the lower-energy weighted spectra. The reduction of chemical potential enhances the ${\overline{\nu }}_e$ emission while suppressing that of ${\nu }_e$, thereby driving an increase in the electron fraction behind the stalled shock at $\sim 30–100\mathrm{km}$. This further amplifies $⟨E_{{\nu }_e}⟩$ through an increased electron density. Consequently, magnetic fields amplify $L_{{\nu }_e}$ by increasing both ${\mathcal{L}}_{{\nu }_e}$ and $⟨E_{{\nu }_e}⟩$, whereas for ${\overline{\nu }}_e$, the rise in ${\mathcal{L}}_{{\overline{\nu }}_e}$ is offset by a decreased $⟨E_{{\overline{\nu }}_e}⟩$, leading to a minimal change in $L_{{\overline{\nu }}_e}$. A systematic parameter scan of dipole field configurations suggests that, for $r_0>30\mathrm{km}$, $⟨E_{{\overline{\nu }}_e}⟩$ is significantly suppressed and $L_{{\nu }_e}$ is enhanced if $B_0\ge 2.7\times {10}^{16}\mathrm{G}$. These magnetic effects become negligible for $B_0$ below $\sim 7.4\times {10}^{15}\mathrm{G}$.

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• Novae & supernovae