Negative-energy waves in a magnetized, homogeneous plasma
The general expression for the second-order wave energy of a Vlasov-Maxwell system derived by Morrison and Pfirsch is evaluated for the case of a magnetised, homogeneous plasma. It is shown again that negative-energy waves (which could become nonlinearly unstable and cause anomalous transport) exist for any deviation from monotonicity and/or any (however small) anisotropy in the equilibrium distribution function of any of the particle species. The partly unexpected and particularly interesting feature of the results is that, contrary to the proof of Morrison and Pfirsch, no restricting condition has to be imposed on the perpendicular wave number of the perturbation. Finite gyroradius effects are, therefore, not expected to improve the situation. Anisotropy alone would, however, impose a restriction on the parallel wave number, relating it to the gyroradius.
Bibliographic Reference: Report: IPP6/301 EN (1991) 15 pp.
Availability: Available from Max-Planck-Institut für Plasmaphysik, 8046 Garching bei München (DE)
Record Number: 199111621 / Last updated on: 1994-12-02
Original language: en
Available languages: en