{
  "abstract": "Solar energetic particles (SEPs) are a signature of solar eruptions, and to link them to acceleration mechanisms many studies investigate their injection time at the Sun, t Sun . We assess velocity dispersion analysis (VDA), an often-used method to derive t Sun . We use full-orbit simulations of 1–100 MeV SEP protons in our recent new model of the interplanetary magnetic turbulence superposed on a Parker spiral magnetic field. The turbulence is described analytically as dominant transverse fluctuations that are 2D with respect to the mean field, supplemented with a minor contribution of asymptotically slab turbulence modes. We determine simulated SEP intensities for four turbulence strengths and use VDA to obtain t Sun and the apparent path length s of the SEPs, employing an SEP onset threshold to mimic a realistic energetic proton background before the SEP event. We find that turbulence strongly affects t Sun and s . For weak to strong turbulence, VDA estimates of t Sun are 2–30 minutes after the actual solar injection time, and the path lengths are 0.2–5 au longer than the Parker spiral. For very strong turbulence, the path lengths are > 5 au, considerably longer than those typically obtained from SEP observations. We also investigate the effect of energy dependence of the pre-event proton background, and find that different background spectra result in 5–20 minutes difference in VDA injection times, depending on the heliolongitude. We conclude that in many cases VDA-derived injection times include a significant contribution from turbulence and/or the pre-event background and are not an accurate estimate of the acceleration time.",
  "abstract_shown": true,
  "affiliations": [
    "University of Lancashire"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "T. Laitinen",
      "orcid": "0000-0002-7719-7783"
    },
    {
      "affs": [
        0
      ],
      "name": "S. Dalla",
      "orcid": "0000-0002-7837-5780"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/210xdn8vrkse4.bib",
  "cited_by": 0,
  "doi": "10.3847/2041-8213/aeae2a",
  "fulltext_url": null,
  "id": "210xdn8vrkse4",
  "issns": [
    "2041-8205",
    "2041-8213"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/2041-8213/aeae2a",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Solar and Space Plasma Dynamics"
    ]
  ],
  "openalex": "W7134276801",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/2041-8213/aeae2a/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/210xdn8vrkse4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:13Z",
      "native_id": "10.3847/2041-8213/aeae2a",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/2041-8213/aeae2a"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Solar and Space Plasma Dynamics",
      "subfield": "stellar"
    }
  ],
  "title": "Velocity Dispersion of Solar Energetic Particles in the Turbulent Heliosphere",
  "title_text": "Velocity Dispersion of Solar Energetic Particles in the Turbulent Heliosphere",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:13Z",
  "url": "https://research.draconitic.com/paper/210xdn8vrkse4",
  "venue": "The Astrophysical Journal Letters",
  "versions": []
}