Phase mixing and echoes in a pure electron plasma

Journal Article · Sun May 15 04:00:00 EDT 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1885006· OSTI ID:20736561

Yu, J H; Driscoll, C F; O'Neil, T M ^[1]

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1. Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, California 92093 (United States) and Physics Department and Institute for Pure and Applied Physical Sciences, University of California at San Diego, La Jolla, California 92093 (United States)

The two-dimensional (2D) fluid echo is a spontaneous appearance of a diocotron wave after two externally excited waves have damped away, explicitly demonstrating the reversible nature of spatial Landau damping. The inviscid damping, or phase mixing, is directly imaged by a low-noise charge-coupled device camera, which shows the spiral wind-up of the density perturbation. Surprisingly, the basic echo characteristics agree with a simple nonlinear ballistic theory that neglects all collective (i.e., mode) effects. Also, the simple 2D picture is violated by end confinement fields that cause v{sub z}-dependent {theta} drifts, so the observed echo must be interpreted as a superposition of separately damping and separately echoing velocity classes. The maximal echo lifetimes agree with a theory describing weak collisional velocity scattering between velocity classes. In addition, large second wave excitations degrade the echo up to 5x faster than collisions.

• OSTI ID: 20736561
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTRONS
ION ACOUSTIC WAVES
LANDAU DAMPING
NONLINEAR PROBLEMS
PLASMA