Magnetic Stress in Magnetars Compared with the Critical Shear Density of the Bound

Magnetars carry the strongest known magnetic fields, and magnetic stress is a genuine source of anisotropy in a neutron star, which makes it the one stellar agent that speaks the same language as shear. This paper converts magnetic energy density to an equivalent mass density for fields from 1e10 to 1e12 T and compares it with the critical shear density of the bound, 2.43e+57 kg per cubic metre on the neutron branch. At 1e11 T, a strong magnetar field, the equivalent density is 4.43e+10 kg per cubic metre, a fraction 1.82e-47 of the critical shear density. Reaching the critical density magnetically would require a field of 2.34e+34 T. Magnetic stress can deform, crack and flare a neutron star, but it cannot approach the shear scale at which a torsion bounce would fail. Simulated from stated assumptions, not measured.