The Origin Magnetars: the role of anisotropic neutron superfluid of neutron stars

Abstract

We estimate the strength of the induced magnetic field due to the total induced magnetic moment of the anisotropic ($^3PF^2$) neutron superfluid interior of neutron stars. The induced magnetic field of the neutron stars is found as follows. $B^{(in)} = \fracη{T_7 - η}B^{(0)} ,\begin{array}{*{20}c}{} & {η=} \ \end{array}\frac{m(^3 P_2 )}{0.1m_{Sun}}R_{NS,6}^{- 3} $ ($T_7$ denotes the interior temperature of the neutron star in unit of 10$^7$ K). The induced magnetic field will gradually increase with the temperature of the neutron star decreasing in their late evolutionary stage. A magnetar may appear in a condition when $T_7 \to η$. The upper limit of the induced magnetic field of $^3P^2$ superfluid is $3.35 \time 10^{14} η$.