{
  "annotation_id": "8b47c9dc-ddbd-4b49-97f6-4343fe60f6bb",
  "date_created": "2026-03-02T18:01:14.067000Z",
  "date_modified": "2026-03-02T18:01:14.067000Z",
  "file_hash": "2dbdee13f29540957c6996a555df42ab254ee8abda5de8cbf3842bce5a4e7eba",
  "private": false,
  "record": {
    "abstract": "This paper gives a pedagogic review of the envelope formalism for excitation\nof zonal flows by nonlinear interactions of plasma drift waves or Rossby waves,\ndescribed equivalently by the Hasegawa-Mima (HM) equation or the\nquasigeostrophic barotropic potential vorticity equation, respectively. In the\nplasma case a modified form of the HM equation, which takes into account\nsuppression of the magnetic-surface-averaged electron density response by a\nsmall amount of rotational transform, is also analyzed. Excitation of zonal\nmean flow by a modulated wave train is particularly strong in the modified HM\ncase. A local dispersion relation for a coherent wave train is calculated by\nlinearizing about a background mean flow and used to find the nonlinear\nfrequency shift by inserting the nonlinearly excited mean flow. Using the\ngeneric nonlinear Schroedinger equation about a uniform carrier wave, the\ncriterion for instability of small modulations of the wave train is found, as\nis the maximum growth rate and phase velocity of the modulations and zonal\nflows, in both the modified and unmodified cases.",
    "arxiv_id": "physics/0610016",
    "authors": [
      "R. L. Dewar",
      "R. F. Abdullatif"
    ],
    "categories": [
      "physics.plasm-ph",
      "physics.ao-ph"
    ],
    "doi": "10.1142/9789812771025_0017",
    "title": "Zonal flow generation by modulational instability",
    "url": "https://arxiv.org/abs/physics/0610016"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "f3ef704f-e8a5-48c8-a93b-727484398d16",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}