Harmonic generation and parametric decay are examined in a toroidal ACT‐1 plasma using electrostatic plate antennas. The harmonic generation, which is consistent with sheath rectification, is sufficiently strong that the nonlinearly generated harmonic modes themselves decay parametrically. Resonant and nonresonant parametric decay of the second harmonic are observed and compared with uniform pump theory. Resonant decay of lower‐hybrid waves into lower‐hybrid waves and slow ion‐cyclotron waves is seen for the first time. Surprisingly, the decay processes are nonlinearly saturated, indicating absolute instability.
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© 1984 American Institute of Physics.
1984
American Institute of Physics
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