PPPL-3378 is available in <a href="PPPL-3378.pdf">pdf</a> or 
<a href="PPPL-3378.ps">postscript</a> formats.

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<b>Excitation of Zonal Flow by Drift Waves in Toroidal Plasmas</b>
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<p><b>Authors:</b> Liu Chen, Zhihong Lin, and Roscoe White</p>

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<b>Date of PPPL Report:</b> November 1999</p>

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<b>NOTE: Revised version dated November 22, 1999</b>
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<b>Published in:</b> Phys. Plasmas <b>7</B> (August 2000) 3129-3132. (Note: Authors changed to: L. Chen, Z.H. Lin, and R. White.)</p>
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An analytical dispersion relation is derived which shows that, in toroidal plasmas, zonal flows can be spontaneously excited via modulations in the radial envelope of a single-<i>n</i> coherent drift wave, with <i>n</i> the toroidal mode number. Predicted instability features are verified by 3D global gyrokinetic simulations of the ion-temperature-gradient mode. Nonlinear equations for mode amplitudes demonstrate saturation of the linearly unstable pump wave and bursting behaviour in the drift-wave intensity and zonal flows.

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