THE MICROSCOPIC FRICTION PARAMETERS OF ROTON-VORTEX INTERACTIONS IN SUPERFLUID-HELIUM

We obtain the values of the microscopic mutual friction parameters D-l and D' by using the same approach as Ferrell and Kyung which analytic ally represented the distribution of the transverse momentum transfer and which was shown to be in agreement with the computer-simulation re sult of Samuels and Donnelly. The long-range part D-l of the longitudi nal microscopic friction parameter due to scattering from the velocity field of the vortex is shown to be equal to D-1 found by Samuels and Donnelly. We present by introducing the total transverse cross-section , the transverse microscopic friction parameter D' which Samuels and D onnelly did not include in their calculation for the microscopic mutua l friction parameter, and show the magnitude of D' to be close to the result given by Hillel and Vinen for a vortex with a roton-absorbing c ore.