2025/01/07 by P. Steinbrunner, T.M. O'Neil, T. M. O’Neil · 1 citation
Physics and Astronomy · #Atomic and Molecular Physics #Atomic physics #Condensed matter physics #Dipole #Dust and Plasma Wave Phenomena #Electron temperature #Instability #Magnetic confinement fusion research #Magnetic field #Mechanics #Physics #Plasma #Plasma stability #Quantum mechanics #Tokamak
paper · pdf · doi:10.1017/s0022377824001405
published in Journal of Plasma Physics 91(1) (Cambridge University Press)
openalex publication_date 2025/01/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
We investigate the global stability properties of an electron–positron pair plasma in the linear regime. The plasma is confined by the magnetic field of an infinitely long wire. This configuration is the large-aspect-ratio limit of the levitated dipole experiment of the APEX collaboration. The stability is governed by the diocotron mode and the interchange mode. The diocotron mode dominates in the case of a cold, non-neutral plasma. For specific density profiles we find analytic solutions. We derive a necessary condition for instability and find unstable solutions if the plasma forms a thin shell around the wire. Solutions for arbitrary density profiles with finite temperature are obtained numerically. We find that finite-temperature effects stabilise the diocotron mode. The interchange mode, on the other hand, dominates if the plasma is neutral and has a finite temperature. This mode becomes unstable for a steep-enough density gradient, that is aligned with the gradient of the magnetic field strength and is stabilised by the equilibrium E× B drift of a non-neutral plasma.