  The Hosking integral, which characterizes magnetic helicity fluctuations in
subvolumes, is known to govern the decay of magnetically dominated turbulence.
Here we show that, when the evolution of the magnetic field is controlled by
the motion of electrons only, as in neutron star crusts, the decay of the
magnetic field is still controlled by the Hosking integral, but now it has
effectively different dimensions than in ordinary magnetohydrodynamic (MHD)
turbulence. This causes the correlation length to increase with time $t$ like
$t^{4/13}$ instead of $t^{4/9}$ in MHD. The magnetic energy density decreases
like $t^{-10/13}$, which is slower than in MHD, where it decays like
$t^{-10/9}$. These new analytic results agree with earlier numerical
simulations for the nonhelical Hall cascade.
