{
  "annotation_id": "d1f46ef1-3634-4f6e-be09-fe1917d40f9b",
  "date_created": "2026-03-02T18:00:42.673000Z",
  "date_modified": "2026-03-02T18:00:42.673000Z",
  "file_hash": "c009d610659cd9e60a694329ade9a7012c65741492be73e9b525469d85651ac4",
  "private": false,
  "record": {
    "abstract": "It is shown that electric current flowing along an axially non-uniform\nmagnetic flux tube produces an associated non-linear, non-conservative axial\nMHD force which pumps plasma from regions where the flux tube diameter is small\nto regions where it is large. In particular, this force will ingest plasma into\nthe ends of a fat, initially potential flux tube and then pump the ingested\nplasma towards the middle bulge, thereby causing mass accumulation at the\nbulge. The ingested plasma convects frozen-in toroidal magnetic flux which\naccumulates at the middle as well. Flux accumulation at the bulge has the\nremarkable consequence of causing the bulge to diminish so that the flux tube\nbecomes axially uniform as observed in coronal loops. Stagnation of the\nconvergent plasma flow at the middle heats the plasma. A small number of tail\nparticles bouncing synchronously between approaching fluid elements can be\nFermi-accelerated to very high energies. Since driving a current along a flux\ntube is tantamount to helicity injection into the flux tube, this mass\ningestion, heating, and straightening should be ubiquitous to helicity\ninjection processes.",
    "arxiv_id": "physics/0212093",
    "authors": [
      "P. M. Bellan"
    ],
    "categories": [
      "physics.plasm-ph"
    ],
    "doi": "10.1016/S0273-1177(03)90627-2",
    "title": "Why helicity injection causes coronal flux tubes to develop an axially   invariant cross-section",
    "url": "https://arxiv.org/abs/physics/0212093"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "c9f34052-0dd2-4f6d-8289-dda465949430",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}