Coronal Holes According to Chromospheric Observations

Baranovskii, E. A.; Gopasyuk, O. S.; Shtertser, N. I.

doi:10.1007/s10511-019-09576-5

Cited by 3 publications

(9 citation statements)

References 19 publications

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“…The results of these two studies agree well with our results, especially with CH2_best in Table 2. In addition, Baranovskii et al (2019) found that the density of observed CHs in the solar chromosphere is 2 – 3 times lower than that of QS. Our results (Table 2) give a CH density 1–1.7 times lower than the QS value, being below the minimum value found by Baranovskii et al (2019).…”

Section: Discussionmentioning

confidence: 99%

“…The radiative transfer equation is then solved giving brightness temperature predictions. The first widely used atmospheric model of this type was the Vernazza-Avrett-Loeser (VAL) model (Vernazza et al 1981) and in each subsequent decade new and improved models have been published: the Fontenla-Avrett-Loeser (FAL) model (Fontenla et al 1993), the Avrett-Loeser (AL) model (Avrett & Loeser 2008), and the Avrett-Tian-Landi-Curdt-Wülser (ATLCW) model (Avrett et al 2015). In addition, a modification of this class of models was developed by Selhorst et al (2005) specifically to include spicules and to cover radio frequencies in the 2-400 GHz range (Selhorst-Silva-Costa (SSC) model).…”

Section: Introductionmentioning

confidence: 99%

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Calculated brightness temperatures of solar structures compared with ALMA and Metsähovi measurements

Matković,

Brajša,

Kuhar

et al. 2024

Astron Nachr

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The Atacama Large Millimeter/submillimeter Array (ALMA) allows for solar observations in the wavelength range of 0.3–10 mm, giving us a new view of the chromosphere. The measured brightness temperature at various frequencies can be fitted with theoretical models of density and temperature versus height. We use the available ALMA and Metsähovi measurements of selected solar structures (quiet sun (QS), active regions (AR) devoid of sunspots, and coronal holes (CH)). The measured QS brightness temperature in the ALMA wavelength range agrees well with the predictions of the semiempirical Avrett–Tian–Landi–Curdt–Wülser (ATLCW) model, better than previous models such as the Avrett–Loeser (AL) or Fontenla–Avrett–Loeser model (FAL). We scaled the ATLCW model in density and temperature to fit the observations of the other structures. For ARs, the fitted models require 9%–13% higher electron densities and 9%–10% higher electron temperatures, consistent with expectations. The CH fitted models require electron densities 2%–40% lower than the QS level, while the predicted electron temperatures, although somewhat lower, do not deviate significantly from the QS model. Despite the limitations of the one‐dimensional ATLCW model, we confirm that this model and its appropriate adaptations are sufficient for describing the basic physical properties of the solar structures.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculated brightness temperatures of solar structures compared with ALMA and Metsähovi measurements

Matković,

Brajša,

Kuhar

et al. 2024

Astron Nachr

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“…Согласно эмпирическим моделям атмосфер спокойного Солнца и КД существенное отличие температуры в КД начинается на уровне слоя с температурой, превышающей 10 5 K [4]. На уровне хромосферы в полярной КД, по сравнению с невозмущенной хромосферой, температура ниже на 500-1500 К, а плотность ниже в 2-3 раза [5].…”

Section: Doi: 1031725/0552-5829-2020-69-72unclassified

“…Участки КД, в которых определись средние относительные интенсивности, располагались на расстоянии ±10 от центрального меридиана и на широтах 40-43 для полярной КД и -5-5 для экваториальных КД. Средние относительные интенсивности полярных (кружки; полые -данные из [5]) и экваториальных (треугольники) КД представлены на рис. 1.…”

Section: Doi: 1031725/0552-5829-2020-69-72unclassified

“…Расчет моделей хромосферы этой КД для трех моментов ее эволюции показал, что по всей высоте хромосферы температура и плотность в КД ниже, чем в невозмущенной хромосфере[5]. В настоящем исследовании ряд наблюдательных данных полярной КД был расширен.…”

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