The Re-Entrant Normal Flapping Mode in the Dipolar Boundary Layers of 3He-A

Research output: Contribution to journalArticle


  • J.P. Pekola

  • K. Torizuka
  • J. M. Kyynarainen
  • A. J. Manninen
  • W. Wojtanowski
  • G. K. Tvalashvili

Research units

  • University of Opole
  • Georgian National Academy of Sciences


Zero sound experiments on superfluid 3He-A at low pressures (<3 bar) and in strong magnetic fields (>0.3T) show an increase in the attenuation at low temperatures (6 0.4 mK) which has been a puzzle until the present experiment. Coupling of the re-entrant normal flapping (NFL) mode to zero sound in a geometry where sound propagates in the direction of the magnetic field is shown to arise from a boundary layer at the walls whose thickness is about the dipolar coherence length D, of 3He-A. We estimate the value oft; at low temperatures and at low and intermediate pressures. We have also studied the nonlinearity of sound propagation near the NFL mode and found a reversal of it when passing the mode.


Original languageEnglish
Pages (from-to)155-160
Number of pages6
Issue number2
Publication statusPublished - 1990
MoE publication typeA1 Journal article-refereed

ID: 4392270