{
  "id": "1710.04067",
  "version": "v1",
  "published": "2017-10-11T13:58:07.000Z",
  "updated": "2017-10-11T13:58:07.000Z",
  "title": "H$α$ and H$β$ emission in a C3.3 solar flare: comparison between observations and simulations",
  "authors": [
    "Vincenzo Capparelli",
    "Francesca Zuccarello",
    "Paolo Romano",
    "Paulo J. A. Simoes",
    "Lyndsay Fletcher",
    "David Kuridze",
    "Mihalis Mathioudakis",
    "Peter H. Keys",
    "Gianna Cauzzi",
    "Mats Carlsson"
  ],
  "comment": "14 pages, 17 figures",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "The Hydrogen Balmer series is a basic radiative loss channel from the flaring solar chromosphere. We report here on the analysis of an extremely rare set of simultaneous observations of a solar flare in the H${\\alpha}$ and H${\\beta}$ lines at high spatial and temporal resolution, which were acquired at the Dunn Solar Telescope. Images of the C3.3 flare (SOL2014-04-22T15:22) made at various wavelengths along the H${\\alpha}$ line profile by the Interferometric Bidimensional Spectrometer (IBIS) and in the H${\\beta}$ with the Rapid Oscillations in the Solar Atmosphere (ROSA) broadband imager are analyzed to obtain the intensity evolution. The H${\\alpha}$ and H${\\beta}$ intensity excesses in three identified flare footpoints are well correlated in time. We examine the ratio of H${\\alpha}$ to H${\\beta}$ flare excess, which was proposed by previous authors as a possible diagnostic of the level of electron beam energy input. In the stronger footpoints, the typical value of the the H${\\alpha}$/H${\\beta}$ intensity ratio observed is $\\sim 0.4-0.5$, in broad agreement with values obtained from a RADYN non-LTE simulation driven by an electron beam with parameters constrained (as far as possible) by observation. The weaker footpoint has a larger H${\\alpha}$/H${\\beta}$ ratio, again consistent with a RADYN simulation but with a smaller energy flux. The H${\\alpha}$ line profiles observed have a less prominent central reversal than is predicted by the RADYN results, but can be brought into agreement if the H${\\alpha}$-emitting material has a filling factor of around 0.2--0.3.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-10-11T13:58:07.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "solar flare",
      "observation",
      "radyn non-lte simulation driven",
      "electron beam energy input",
      "comparison"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}