Exploration of solar chromosphere using high resolution spectroscopic observations
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| Format: | Artículo científico |
| Sprache: | en |
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Sociedade Brasileira de Física
2004
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| _version_ | 1876473593433423872 |
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| author | F. C. R. Fernandes |
| author_facet | F. C. R. Fernandes |
| contents | Exploration of solar chromosphere using high resolution spectroscopic observations F. C. R. Fernandes H. S. Sawant F. R. H. Madsen J. R. Cecatto Física, Astronomía y Matemáticas Brazilian Solar Spectroscope (BSS), operating in the frequency range of (1000 - 2500) MHz with high timeand frequency resolutions, has observed various fine structures showing intensity variations as functions of time and frequency. Here we are reporting radio bursts observed by BSS, from August to October/2001, exhibitingfine structures with total duration of the order of 300 ms, covering a frequency range of ~ 200 MHz. Thesecharacteristics are similar to those of the narrow band type III bursts observed above 1000 MHz. Hence thesefine structures are variants of decimetric narrow band type III-like bursts. The fine structures observed exhibit variation of intensity as a function of frequency and curvatures in the frequency-time plane. These fine structures are explained as a propagation effect. We suggest that these structures are the signatures of the chromospheric density inhomogeneities lying in the line-of-sight path between the observer and the radio source. If the emittedfrequencies are lower than the plasma frequency of the inhomogeneity, there will be absorption over a certainband, corresponding to the dimension of the inhomogeneity. The curved like structures are due to lower groupvelocities of the lower frequencies in the density inhomogeneities. The estimated scale sizes of the irregularities obtained are of the order of 101 - 104 km. Thus an alternative method to total solar eclipse observation is suggested for investigations of chromospheric density irregularities. 2004 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46434807 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.4B Vol.34 |
| format | Artículo científico |
| id | redalyc_46434807 |
| institution | Redalyc |
| language | en |
| publishDate | 2004 |
| publisher | Sociedade Brasileira de Física |
| spellingShingle | Exploration of solar chromosphere using high resolution spectroscopic observations F. C. R. Fernandes Física, Astronomía y Matemáticas Exploration of solar chromosphere using high resolution spectroscopic observations F. C. R. Fernandes H. S. Sawant F. R. H. Madsen J. R. Cecatto Física, Astronomía y Matemáticas Brazilian Solar Spectroscope (BSS), operating in the frequency range of (1000 - 2500) MHz with high timeand frequency resolutions, has observed various fine structures showing intensity variations as functions of time and frequency. Here we are reporting radio bursts observed by BSS, from August to October/2001, exhibitingfine structures with total duration of the order of 300 ms, covering a frequency range of ~ 200 MHz. Thesecharacteristics are similar to those of the narrow band type III bursts observed above 1000 MHz. Hence thesefine structures are variants of decimetric narrow band type III-like bursts. The fine structures observed exhibit variation of intensity as a function of frequency and curvatures in the frequency-time plane. These fine structures are explained as a propagation effect. We suggest that these structures are the signatures of the chromospheric density inhomogeneities lying in the line-of-sight path between the observer and the radio source. If the emittedfrequencies are lower than the plasma frequency of the inhomogeneity, there will be absorption over a certainband, corresponding to the dimension of the inhomogeneity. The curved like structures are due to lower groupvelocities of the lower frequencies in the density inhomogeneities. The estimated scale sizes of the irregularities obtained are of the order of 101 - 104 km. Thus an alternative method to total solar eclipse observation is suggested for investigations of chromospheric density irregularities. 2004 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46434807 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.4B Vol.34 |
| title | Exploration of solar chromosphere using high resolution spectroscopic observations |
| topic | Física, Astronomía y Matemáticas |
| url | https://www.redalyc.org/articulo.oa?id=46434807 |