{
  "id": "1710.07717",
  "version": "v1",
  "published": "2017-10-20T22:16:36.000Z",
  "updated": "2017-10-20T22:16:36.000Z",
  "title": "Magnetic field amplification in supernova remnants",
  "authors": [
    "Siyao Xu",
    "Alex Lazarian"
  ],
  "comment": "8 pages, 2 figures, accepted for publication in ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Based on the new findings on the turbulent dynamo in \\citet{XL16}, we examine the magnetic field amplification in the context of supernova remnants. Due to the strong ion-neutral collisional damping in the weakly-ionized interstellar medium, the dynamo in the preshock turbulence remains in the damping kinematic regime, which leads to {\\it a linear-in-time growth of the magnetic field strength}. The resultant magnetic field structure enables effective diffusion upstream and shock acceleration of cosmic rays to energies above the \"knee\". Differently, the nonlinear dynamo in the postshock turbulence leads to {\\it a linear-in-time growth of the magnetic energy} due to the turbulent magnetic diffusion. Given a weak initial field strength in the postshock region, the magnetic field saturates at a significant distance from the shock front as a result of the inefficiency of the nonlinear dynamo. This result is in a good agreement with existing numerical simulations and well explains the X-ray spots detected far behind the shock front.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-10-20T22:16:36.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "magnetic field amplification",
      "supernova remnants",
      "structure enables effective diffusion",
      "enables effective diffusion upstream",
      "field structure enables effective"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}