DYNAMICS OF THE INTERACTIONS OF ROTONS WITH QUANTIZED VORTICES IN HELIUM-II

We consider the theory of mutual friction in helium II which accounts for the coupling of the normal and superfluid flows by means of quantized vortices. Numerical simulations of roton-vortex interactions suggest a simple new expression which accounts for most mutual friction at low temperatures. By carefully separating that which can be known at the present time from that which cannot be known until the structure of quantized vortices is understood, we are able to account for mutual friction in a semiempirical way at all temperatures and pressures. © 1990 The American Physical Society.