{
  "id": "astro-ph/0002529",
  "version": "v1",
  "published": "2000-02-29T20:55:58.000Z",
  "updated": "2000-02-29T20:55:58.000Z",
  "title": "Spherical, Oscillatory $α^2$-Dynamo Induced by Magnetic Coupling Between a Fluid Shell and an Inner Electrically Conducting Core: Relevance to the Solar Dynamo",
  "authors": [
    "G. Schubert",
    "K. Zhang"
  ],
  "comment": "7 pages, 1 postscript figure",
  "doi": "10.1086/312570",
  "categories": [
    "astro-ph"
  ],
  "abstract": "A two-layer spherical $\\alpha^2$-dynamo model consisting of an inner electrically conducting core (magnetic diffusivity $\\lambda_i$ and radius $r_i$) with $\\alpha = 0$ surrounded by an electrically conducting spherical shell (magnetic diffusivity $\\lambda_o$ and radius $r_o$) with a constant $\\alpha$ is shown to exhibit oscillatory behavior for values of $\\beta = \\lambda_i/\\lambda_o$ and $r_i/r_o$ relevant to the solar dynamo. Time-dependent dynamo solutions require $r_i/r_o \\geq 0.55$ and $\\beta \\leq O(1)$. For the Sun, $r_i/r_o$ is about 0.8 and $\\beta\\approx 10^{-3}$. The time scale of the oscillations matches the 22 year period of the sunspot cycle for $\\lambda_0 = O(10^2 km^2 s^{-1}$). It is unnecessary to hypothesize an $\\alpha\\omega$-dynamo to obtain oscillatory dynamo solutions; an $\\alpha^2$-dynamo suffices provided the spherical shell region of dynamo action lies above a large, less magnetically diffusive core, as is the case for the solar dynamo.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2000-02-29T20:55:58.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "inner electrically conducting core",
      "solar dynamo",
      "fluid shell",
      "magnetic coupling"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 544837
    }
  }
}