Plasma and Fusion Research

Volume 21, 1203039 (2026)

Rapid Communications

Collisional Effects on the Drift Hole Dynamics in Magnetically Confined Plasmas
Yusuke KOSUGA1), Kimitaka ITOH2)
1)
Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
2)
Chubu University, Kasugai, Aichi 487-8501, Japan
(Received 8 April 2026 / Accepted 29 April 2026 / Published 24 July 2026)

Abstract

The effect of collisions on the dynamics of phase space structures in inhomogeneous magnetized plasmas is analyzed. A drift hole is used as an example, and subcritical bifurcation associated with a drift hole is analyzed in the presence of small but finite collisional damping. It is shown that there exists a critical collisionality, below which finite amplitude turbulent state can be sustained even in the absence of linear instability. This gives a crude estimate on how “collisionless” is collisionless for nonlinear dynamics of phase space structures to appear.

Keywords

plasma and fusion, phase space dynamics, subcritical excitation of turbulence, a drift hole, collisional effect

DOI: 10.1585/pfr.21.1203039

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References

  • [1] L. Landau, J. Phys. U.S.S.R. 10, 25 (1946).
  • [2] I.B. Bernstein et al., Phys. Rev. 108, 546 (1957).
  • [3] T.H. Dupree, Phys. Rev. Lett. 25, 789 (1970).
  • [4] B.B. Kadomtsev and O.P. Pogutse, Phys. Rev. Lett. 25, 1155 (1970).
  • [5] T.H. Dupree, Phys. Fluids 15, 334 (1972).
  • [6] H.L. Berk et al., Phys. Lett. A 234, 213 (1997).
  • [7] M. Lesur and P.H. Diamond, Phys. Rev. E 87, 031101(R) (2013).
  • [8] H. Biglari et al., Phys. Fluids 31, 2644 (1988).
  • [9] P.W. Terry et al., Phys. Fluids B 2, 2048 (1990).
  • [10] Y. Kosuga et al., Nucl. Fusion 57, 072006 (2017).
  • [11] Y. Kosuga and P.H. Diamond, Phys. Plasmas 19, 072307 (2012).
  • [12] T. Ido et al., Phys. Rev. Lett. 116, 015002 (2016).
  • [13] Y. Kosuga and K. Itoh, J. Phys. Soc. Jpn. 94, 094501 (2025).
  • [14] K. Itoh and Y. Kosuga, J. Phys. Soc. Jpn. 95, 013501 (2026).
  • [15] V.E. Zakharov and V.I. Karpman, Sov. Phys. JETP 16, 351 (1963).
  • [16] F. Valentini, Phys. Plasmas 15, 022102 (2008).
  • [17] P.H. Diamond et al., Modern Plasma Physics Volume1: Physical Kinetics of Turbulent Plasmas (Cambridge University Press, Cambridge, 2011).