## Abstract

The nonlinear Landau damping and growth of longitudinal waves in a magnetic field is studied experimentally. It is observed that a finite-amplitude cyclotron harmonic wave may decay nonresonantly into a similar, small-amplitude wave. This perturbed wave dan be amplified exponentially by increasing the amplitude of the finite-amplitude wave. Similarly, an externally launched small-amplitude test wave, having the same frequency as the perturbed wave, can be amplified at a comparable rate. The spatial growth of the test wave is in agreement with the predictions of a third-order mode-coupling equation. Using a calibrated interferometer system, the nonlinear Landau damping coupling coefficients (matrix elements) are measured quantitatively, and are found to be in good agreement with theory.

Original language | English |
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Pages (from-to) | 297-303 |

Number of pages | 7 |

Journal | Physics of Fluids |

Volume | 15 |

Issue number | 2 |

Publication status | Published - 1972 |

## ASJC Scopus subject areas

- Condensed Matter Physics
- Physics and Astronomy(all)
- Mechanics of Materials
- Computational Mechanics
- Fluid Flow and Transfer Processes