  Spin-torque-biased magnetic dynamics in an easy-plane ferromagnet (EPF) is
theoretically studied in the presence of a weak in-plane anisotropy. While this
anisotropy spoils U(1) symmetry thereby quenching the conventional spin
superfluidity, we show that the system instead realizes a close analog of a
long Josephson junction (LJJ) model. The traditional magnetic-field and
electric-current controls of the latter map respectively onto the symmetric and
antisymmetric combinations of the out-of-plane spin torques applied at the ends
of the magnetic strip. This suggests an alternative route towards realizations
of superfluid-like transport phenomena in insulating magnetic systems. We study
spin-torque-biased phase diagram, providing an analytical solution for static
multidomain phases in the EPF. We adapt an existing self-consistency method for
the LJJ to develop an approximate solution for the EPF dynamics. The LJJ-EPF
mapping allows us to envision superconducting circuit functionality at elevated
temperatures. The results apply equally to antiferromagnets with suitable
effective free energy in terms of the N\'{e}el order instead of magnetization.
