Electrostatic stability of electron–positron plasmas in dipole geometry. (4th March 2018)

• Record Type: Journal Article
• Authors: Mishchenko, Alexey; Plunk, Gabriel G.; Helander, Per
• Is Part Of: Journal of plasma physics. Volume 84:Number 2(2018)
• Publication Date: 2018-03-04
• Subjects: plasma instabilities; Plasma (Ionized gases) -- Periodicals; 530.4405
• DOI: 10.1017/S0022377818000193
• Languages: English
• ISSNs: 0022-3778

Abstract

Abstract : The electrostatic stability of electron–positron plasmas is investigated in the point-dipole and Z-pinch limits of dipole geometry. The kinetic dispersion relation for sub-bounce-frequency instabilities is derived and solved. For the zero-Debye-length case, the stability diagram is found to exhibit singular behaviour. However, when the Debye length is non-zero, a fluid mode appears, which resolves the observed singularity, and also demonstrates that both the temperature and density gradients can drive instability. It is concluded that a finite Debye length is necessary to determine the stability boundaries in parameter space. Landau damping is investigated at scales sufficiently smaller than the Debye length, where instability is absent.