It is confirmed experimentally that the self-interaction of electron Bernstein waves occurs by means of nonlinear cyclotron (Landau) damping. This wave-particle interaction occurs in a relatively broad frequency range: $1.46<\mathrm{}\frac{\omega }{{\omega }_c}<1.54\mathrm{}$, $1.60<\mathrm{}\frac{\omega }{{\omega }_c}<1.75\mathrm{}$. The virtual wave is observed most strongly at the half-harmonic electron cyclotron frequency near $\frac{\omega }{{\omega }_c}\cong 1.5$. Although this self-interaction always occurs for $\frac{k_{\parallel }{v}_t}{{\omega }_c}\lesssim 0.1$, the virtual wave cannot be detected for $\frac{k_{\parallel }{v}_t}{{\omega }_c}\gtrsim 0.15$.

• Received 15 March 1988

DOI:https://doi.org/10.1103/PhysRevLett.61.543