Exact solution for the generalized Bohm criterion in a two-ion-species plasma

Lee D., Oksuz L., Hershkowitz N.

PHYSICAL REVIEW LETTERS, vol.99, no.15, 2007 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 99 Issue: 15
  • Publication Date: 2007
  • Doi Number: 10.1103/physrevlett.99.155004
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Süleyman Demirel University Affiliated: Yes


For a weakly collisional two-ion species plasma, it is shown that the minimum phase velocity of ion acoustic waves (IAWs) at the sheath-presheath boundary is equal to twice the phase velocity in the bulk plasma. This condition provides a theoretical basis for the experimental results that each ion species leaves the plasma with a drift velocity equal to the IAW phase velocity in the bulk plasma [D. Lee et al., Appl. Phys. Lett. 91, 041505 (2007)]. It is shown that this result is a consequence of the generalized Bohm criterion and fluid expressions for the IAW phase velocities.