independent of their arrangement. The energy of a bundle of neutron or proton vortices is minimized by a triangular lattice with a unit cell area $$n_{\tau}^{-1}=(\sqrt{3}/2)~d_{\tau}^2.$$ The length of a “basis vector” of such a lattice in a neutron condensate (the neutron inter-vortex distance) is $$\begin{aligned}
   d_n= \left(\frac{\pi\hbar}{\sqrt{3}\, m_n\, \Omega}   \right)^{1/2}.\end{aligned}$$ For the inter-vortex distance in the proton condensate we find $$\begin{aligned}
  d_p=\left(\frac{2\, \Phi_0}{\sqrt{3} \, B}   \right)^{1/2},\end{aligned}$$ where $B$ is the mean magnetic field induction. Using the estimates given in Eqs. (\[eq:AS:nn\]) and (\[eq:AS:np\]) we find that the neutron and proton inter-vortex distances are $d_n \sim 10^{-2}-10^{-3}$ cm and $d_p\sim 10^{-9}$ cm respectively. For typical values of the microscopic parameters the penetration depth is of the order of 100 fm, therefore the conditions $\xi_n\ll d_n$ and $\xi_p\ll {\rm min }( \lambda, ~d_p)$ are satisfied and the use of the hydrodynamics on the local scale is valid. It is also clear that the global hydrodynamics can be applied on the scales that are much larger than $d_n$ (a fraction of millimeter).

The remainder of this review concentrates on the physics of the global hydrodynamic scale and on neutral superfluids only, as the dominant fraction of the moment of inertia of a 