{
  "abstract": "Convectively driven motions in the solar photosphere can generate broad-band Doppler variability across the chromosphere, transition region, and corona. Here, we investigate this variability using ‘Sun-as-a-star’ observations from the Extreme Ultraviolet Variability Experiment (EVE) aboard the Solar Dynamics Observatory, constructing high signal-to-noise Doppler power spectra by incoherently averaging spectra from 3-h sequences of the centroid wavelengths of emission lines that span wavelengths 35–104 nm. The spectra reveal a broad power-spectral continuum with two ‘Harvey’ components, one of which extends to the Nyquist frequency at 50 mHz with a steep power-law tail. All emission lines have substantial power both above and below the nominal acoustic cutoff frequency at 5 mHz, but none of the power spectra show maxima corresponding to p-mode or chromospheric 3-min oscillations. Lines formed in the corona, as compared with those of the chromosphere/transition region, have substantially less Doppler amplitude in the Harvey spectrum associated with granulation-scale convection. Based on the observed continuum, there is no evidence (in any of the 26 lines studied) for Kolmogorov turbulence, which predicts a flat continuum component with Doppler variance $\\langle {v^2}\\rangle \\, \\propto \\, f^{-5/3}$ as a function of frequency f. The total inferred RMS velocities (${\\gt} 0.1$ mHz) are roughly consistent with coronal ‘microturbulence’ estimates from excess line widths. These observations provide the first clear detection of Sun-as-a-star extreme ultraviolet (EUV) Doppler variability above $\\sim$10 mHz and demonstrate the potential of full-disc EUV spectroscopy to probe turbulent energy transport throughout a stellar atmosphere. The predominance of the Harvey spectrum, a signature of photospheric convection, likely results from limb brightening of the Doppler variance due to horizontal flows in the upper solar atmosphere.",
  "abstract_shown": true,
  "affiliations": [
    "SUPA School of Physics & Astronomy, University of Glasgow , Glasgow G12 8QQ ,",
    "Space Science Laboratory, University of California , Berkeley, CA 94720 ,",
    "Centre for Fusion, Space, and Astrophysics, University of Warwick , Coventry, CV4 7AL ,",
    "Rosseland Centre for Solar Physics, University of Oslo , PO Box 1029 Blindern, NO-0315 Oslo ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Hugh Hudson",
      "orcid": "0000-0001-5685-1283"
    },
    {
      "affs": [
        2
      ],
      "name": "Anne-Marie Broomhall",
      "orcid": "0000-0002-5209-9378"
    },
    {
      "affs": [
        0,
        3
      ],
      "name": "Lyndsay Fletcher",
      "orcid": "0000-0001-9315-7899"
    },
    {
      "affs": [
        0
      ],
      "name": "David Graham"
    },
    {
      "affs": [
        0
      ],
      "name": "Sargam M Mulay",
      "orcid": "0000-0002-9242-2643"
    },
    {
      "affs": [
        0
      ],
      "name": "Chris Osborne",
      "orcid": "0000-0002-2299-2800"
    },
    {
      "affs": [
        0
      ],
      "name": "Kirsty Williamson"
    },
    {
      "affs": [
        0
      ],
      "name": "Graham Woan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ady34sbhcfbw2.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag1903",
  "fulltext_url": null,
  "id": "ady34sbhcfbw2",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1903/8876086",
  "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": "W7167600521",
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag1903/71668213/stag1903.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-07",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/ady34sbhcfbw2.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:17Z",
      "native_id": "10.1093/mnras/stag1903",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1903/8876086"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Solar and Space Plasma Dynamics",
      "subfield": "stellar"
    }
  ],
  "title": "Signatures of photospheric convection throughout the solar atmosphere: the EVE Sun-as-a-star mHz continuum",
  "title_text": "Signatures of photospheric convection throughout the solar atmosphere: the EVE Sun-as-a-star mHz continuum",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:17Z",
  "url": "https://research.draconitic.com/paper/ady34sbhcfbw2",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": []
}