Integrable, oblique travelling waves in quasi-charge-neutral two-fluid plasmas
- 1Institute of Geophysics and Planetary Physics, University of California Riverside, Riverside CA 92521, USA
- 2Institute of Astronomy, Department of Physics and Centre for Complex Systems, National Central University, Chung-Li, 32054, Taiwan, Republic of China
- 3School of Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
- *work carried out on leave at: IGPP, University of California Riverside, CA, USA
Abstract. A Hamiltonian description of oblique travelling waves in a two-fluid, charge-neutral, electron-proton plasma reveals that the transverse momentum equations for the electron and proton fluids are exactly integrable in cases where the total transverse momentum flux integrals, Py(d) and Pz(d), are both zero in the de Hoffman Teller (dHT) frame. In this frame, the transverse electric fields are zero, which simplifies the transverse momentum equations for the two fluids. The integrable travelling waves for the case Py(d)=Pz(d)=0, are investigated based on the Hamiltonian trajectories in phase space, and also on the longitudinal structure equation for the common longitudinal fluid velocity component ux of the electron and proton fluids. Numerical examples of a variety of travelling waves in a cold plasma, including oscillitons, are used to illustrate the physics. The transverse, electron and proton velocity components ujy and ujz (j=e, p) of the waves exhibit complex, rosette type patterns over several periods for ux. The role of separatrices in the phase space, the rotational integral and the longitudinal structure equation on the different wave forms are discussed.