{
  "abstract": "We review the Enhanced D-alpha (EDA) and Quasi-continuous Exhaust (QCE) H-modes that have recently been achieved in the DIII-D tokamak. These scenarios are free of large type-I edge-localized modes (ELMs) and achieved at high fueling compatible with divertor detachment. This makes them promising operational regimes as ELMs are a major risk for fusion pilot plants (FPPs). Access to EDA H-mode and the associated quasi-coherent mode (QCM) was observed at low heating power barely above the L-H power threshold, and increased density enabled access to EDA H-mode even at higher heating powers. The QCE H-mode was achieved at simultaneously high density and heating power, characterized also by a QCM and small ELMs with transient peaks of the total power into the divertor below about 3MW, in line with observations at ASDEX Upgrade. During the QCE H-mode, the turbulence parameter alpha_t at the separatrix is about 1 and does not separate ELMy or EDA from QCE H-modes well. Peeling ballooning stability calculations suggest that the EDA H-mode pedestal is limited by transport far away from ideal magnetohydrodynamic instability, and the QCE H-mode pedestal operates close to the ballooning branch of the stability boundary. BOUT++ simulations qualitatively reproduce the pressure collapse characteristics of the different regimes and suggest an important role of n ~ 50 resistive ballooning modes localized near the separatrix at the X-point during EDA and QCE H-modes. This work provides a foundation and guidance for further research on the access conditions and physics mechanisms of EDA and QCE H-modes necessary for the extrapolation of these regimes towards an FPP.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.31782",
  "author_total": 22,
  "authors": [
    {
      "name": "N. Leuthold"
    },
    {
      "name": "Z. Li"
    },
    {
      "name": "M. Faitsch"
    },
    {
      "name": "A. Hyatt"
    },
    {
      "name": "C. F. B. Zimmermann"
    },
    {
      "name": "L. Gil"
    },
    {
      "name": "T. Osborne"
    },
    {
      "name": "T. Odstrcil"
    },
    {
      "name": "N. C. Logan"
    },
    {
      "name": "K. Barada"
    },
    {
      "name": "C. Chrystal"
    },
    {
      "name": "R. Gerru"
    },
    {
      "name": "S. Guizzo"
    },
    {
      "name": "R. Hood"
    },
    {
      "name": "L. Huse"
    },
    {
      "name": "S. K. Kim"
    },
    {
      "name": "C. J. Lasnier"
    },
    {
      "name": "A. O. Nelson"
    },
    {
      "name": "C. Paz-Soldan"
    },
    {
      "name": "R. Perillo"
    },
    {
      "name": "B. Victor"
    },
    {
      "name": "T. Wilks"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5e68c1xk2zdpr.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.31782",
  "fulltext_url": null,
  "id": "5e68c1xk2zdpr",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.31782",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.plasm-ph"
    ],
    [
      "openalex",
      "3106|Magnetic confinement fusion research"
    ]
  ],
  "openalex": "W7223695226",
  "pdf_url": "https://arxiv.org/pdf/2610.31782",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5e68c1xk2zdpr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:15Z",
      "native_id": "2610.31782",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.31782"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.plasm-ph",
      "subfield": "plasma"
    }
  ],
  "title": "Overview of Enhanced D-alpha and Quasi Continuous Exhaust H-modes at DIII-D",
  "title_text": "Overview of Enhanced D-alpha and Quasi Continuous Exhaust H-modes at DIII-D",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:15Z",
  "url": "https://research.draconitic.com/paper/5e68c1xk2zdpr",
  "venue": "arXiv",
  "versions": []
}