Kozik, ESvistunov, Boris2024-04-262024-04-262004-01-01https://hdl.handle.net/20.500.14394/40590This is the pre-published version harvested from ArXiv. The published version is located at http://prl.aps.org/abstract/PRL/v92/i3/e035301Kelvin waves (kelvons), the distortion waves on vortex lines, play a key part in the relaxation of superfluid turbulence at low temperatures. We present a weak-turbulence theory of kelvons. We show that nontrivial kinetics arises only beyond the local-induction approximation and is governed by three-kelvon collisions; a corresponding kinetic equation is derived. We prove the existence of Kolmogorov cascade and find its spectrum. The qualitative analysis is corroborated by numeric study of the kinetic equation. The application of the results to the theory of superfluid turbulence is discussed.Physical Sciences and MathematicsPhysicsarticle