{
  "id": "1810.03922",
  "version": "v1",
  "published": "2018-10-09T11:30:49.000Z",
  "updated": "2018-10-09T11:30:49.000Z",
  "title": "Frequency rising sub-THz emission from solar flare ribbons",
  "authors": [
    "E. P. Kontar",
    "G. G. Motorina",
    "N. L. S. Jeffrey",
    "Y. T. Tsap",
    "G. D. Fleishman",
    "A. V. Stepanov"
  ],
  "comment": "6 pages, 3 figures, 2 tables, A&A, accepted",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Observations of solar flares at sub-THz frequencies (mm and sub-mm wavelengths) over the last two decades often show a spectral component rising with frequency. Unlike a typical gyrosynchrotron spectrum decreasing with frequency, or a weak thermal component from hot coronal plasma, the observations can demonstrate a high flux level (up to ~10^4 s.f.u. at 0.4 THz) and fast variability on sub-second time scales. Although, many models has been put forward to explain the puzzling observations, none of them have clear observational support. Here we propose a scenario to explain the intriguing sub-THz observations. We show that the model, based on free-free emission from the plasma of flare ribbons at temperatures 10^4-10^6 K, is consistent with all existing observations of frequency-rising sub-THz flare emission. The model provides a temperature diagnostic of the flaring chromosphere and suggests fast heating and cooling of the dense transition region plasma.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-10-09T11:30:49.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "frequency rising sub-thz emission",
      "solar flare ribbons",
      "observations",
      "dense transition region plasma",
      "sub-thz flare emission"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}