{
  "annotation_id": "9c9200c5-0008-4229-b9c5-82d078121f38",
  "date_created": "2026-03-02T18:00:29.401000Z",
  "date_modified": "2026-03-02T18:00:29.401000Z",
  "file_hash": "b0544fda2a56f2880d3919994bf7ee44a1088644b250f984436f66aaac668992",
  "private": false,
  "record": {
    "abstract": "The EISCAT radar system has been used for the first time in a four-beam\nmeridional mode. The FAST satellite and ALIS imaging system is used in\nconjunction to support the radar data, which was used to identify a main\nionospheric trough. With this large latitude coverage the trough was passed in\n2.5 hours period. Its 3-dimensional structure is investigated and discussed. It\nis found that the shape is curved along the auroral oval, and that the trough\nis wider closer to the midnight sector. The position of the trough coincide\nrather well with various statistical models and this trough is found to be a\ntypical one.",
    "arxiv_id": "physics/0001043",
    "authors": [
      "M. Hedin",
      "I. H\u00e4ggstr\u00f6m",
      "A. Pellinen-Wannberg",
      "L. Andersson",
      "U. Br\u00e4ndstr\u00f6m",
      "B. Gustavsson",
      "\u00c5. Steen",
      "A. Westman",
      "G. Wannberg",
      "T. v Eyken",
      "T. Aso",
      "C. Cattell",
      "C. W. Carlson",
      "D. Klumpar"
    ],
    "categories": [
      "physics.space-ph"
    ],
    "journal_ref": "Adv. Polar Upper Atmos. Res., 14, 2000, pp157--162",
    "title": "3-D extent of the main ionospheric trough--a case study",
    "url": "https://arxiv.org/abs/physics/0001043"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "d609f247-f83d-49c9-ae96-ecaea2391b81",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}