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P: Fachverband Plasmaphysik
P 5: Magnetic Confinement II/HEPP II
P 5.2: Talk
Monday, February 26, 2024, 16:55–17:20, ELP 6: HS 3
Equilibrium and stability of plasma with arbitrary non-neutrality in a levitated dipole trap — •Patrick Steinbrunner1, Thomas O'Neil2, and Matthew Stoneking3 — 1Max Planck Institute for Plasma Physics, Greifswald, Germany — 2University of California San Diego, La Jolla, United States — 3Lawrence University, Appleton, United States
A purely nonneutral plasma can be confined in a global thermal equilibrium state as well as a local thermal equilibrium along magnetic field lines in a magnetic dipole trap. A plasma consisting of a mixture of electrons and positrons, as it is envisioned by the APEX collaboration (A Positron-Electron eXperiment), can only be confined in a local thermal equilibrium state. While global thermal equilibria are maximum entropy states and hence guaranteed to be stable, local thermal equilibria can be unstable.
One of the dominant instabilities, the diocotron mode, was studied to a great extend in the homogeneous magnetic field of a Penning-Malmberg trap. We will focus on the inhomogeneous magnetic field of a z-pinch, which serves as an approximation of the vicinity of a levitated coil. This implies two differences in comparison to a Penning-Malmberg trap. First, grad-B and curvature drifts influence the instability. Second, plasmas of arbitrary nonneutrality can be confined. We found that in the general case of arbitrary nonneutrality, the stability is governed by an interplay between the diocotron and the interchange instability.
Keywords: Pair Plasma; Laboratory Plasmas; Astrophysical Plasmas; Magnetic Confinement; Computational Methods