Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere
We focus here on impulsive phenomena and Quiet-Sun features in the solar transition region, observed with the Interface Region Imaging Spectrograph (IRIS) at 1,400 Å (at formation temperatures of Te ≈ 104–106 K). Summarizing additional literature values we find the following fractal dimensions (in i...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-11-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2022.999319/full |
| _version_ | 1798045373810343936 |
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| author | Markus J. Aschwanden Nived Vilangot Nhalil |
| author_facet | Markus J. Aschwanden Nived Vilangot Nhalil |
| author_sort | Markus J. Aschwanden |
| collection | DOAJ |
| description | We focus here on impulsive phenomena and Quiet-Sun features in the solar transition region, observed with the Interface Region Imaging Spectrograph (IRIS) at 1,400 Å (at formation temperatures of Te ≈ 104–106 K). Summarizing additional literature values we find the following fractal dimensions (in increasing order): DA = 1.23 ± 0.09 for photospheric granulation, DA =1.40 ± 0.09 for chromospheric (network) patterns, DA = 1.54 ± 0.04 for plages in the transition region, DA = 1.56 ± 0.08 for extreme ultra-violet (EUV) nanoflares, DA = 1.59 ± 0.20 for active regions in photospheric magnetograms, and DA = 1.76 ± 0.14 for large solar flares. We interpret low values of the fractal dimension (1.0 ≲ DA ≲ 1.5) in terms of sparse curvi-linear flow patterns, while high values of the fractal dimension (1.5 ≲ DA ≲ 2.0) indicate quasi-space-filling transport processes, such as chromospheric evaporation in flares. Phenomena in the solar transition region appear to be consistent with self-organized criticality (SOC) models, based on their fractality and their size distributions of fractal areas A and (radiative) energies E, which show power law slopes of αAobs=2.51±0.21 (with αAtheo=2.33 predicted), and αEobs=2.03±0.18 (with αEtheo=1.80 predicted). This agreement suggests that brightenings detected with IRIS at 1,400 Å reveal the same nonlinear SOC statistics as their coronal counterparts in EUV. |
| first_indexed | 2024-04-11T23:19:50Z |
| format | Article |
| id | doaj.art-3d4545b4ed9442c683a0e2b4b495ff70 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-04-11T23:19:50Z |
| publishDate | 2022-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-3d4545b4ed9442c683a0e2b4b495ff702022-12-22T03:57:28ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2022-11-01910.3389/fspas.2022.999319999319Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphereMarkus J. Aschwanden0Nived Vilangot Nhalil1Lockheed Martin, Solar and Astrophysics Laboratory (LMSAL), Advanced Technology Center (ATC), Palo Alto, CA, United StatesArmagh Observatory and Planetarium, College Hill, Armagh, United KingdomWe focus here on impulsive phenomena and Quiet-Sun features in the solar transition region, observed with the Interface Region Imaging Spectrograph (IRIS) at 1,400 Å (at formation temperatures of Te ≈ 104–106 K). Summarizing additional literature values we find the following fractal dimensions (in increasing order): DA = 1.23 ± 0.09 for photospheric granulation, DA =1.40 ± 0.09 for chromospheric (network) patterns, DA = 1.54 ± 0.04 for plages in the transition region, DA = 1.56 ± 0.08 for extreme ultra-violet (EUV) nanoflares, DA = 1.59 ± 0.20 for active regions in photospheric magnetograms, and DA = 1.76 ± 0.14 for large solar flares. We interpret low values of the fractal dimension (1.0 ≲ DA ≲ 1.5) in terms of sparse curvi-linear flow patterns, while high values of the fractal dimension (1.5 ≲ DA ≲ 2.0) indicate quasi-space-filling transport processes, such as chromospheric evaporation in flares. Phenomena in the solar transition region appear to be consistent with self-organized criticality (SOC) models, based on their fractality and their size distributions of fractal areas A and (radiative) energies E, which show power law slopes of αAobs=2.51±0.21 (with αAtheo=2.33 predicted), and αEobs=2.03±0.18 (with αEtheo=1.80 predicted). This agreement suggests that brightenings detected with IRIS at 1,400 Å reveal the same nonlinear SOC statistics as their coronal counterparts in EUV.https://www.frontiersin.org/articles/10.3389/fspas.2022.999319/fullmethodsstatistical -fractal dimension -suntransition region -solar granulation -solar photospherefractal dimensionstatistical |
| spellingShingle | Markus J. Aschwanden Nived Vilangot Nhalil Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere Frontiers in Astronomy and Space Sciences methods statistical -fractal dimension -sun transition region -solar granulation -solar photosphere fractal dimension statistical |
| title | Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere |
| title_full | Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere |
| title_fullStr | Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere |
| title_full_unstemmed | Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere |
| title_short | Interface region imaging spectrograph (IRIS) observations of the fractal dimension in the solar atmosphere |
| title_sort | interface region imaging spectrograph iris observations of the fractal dimension in the solar atmosphere |
| topic | methods statistical -fractal dimension -sun transition region -solar granulation -solar photosphere fractal dimension statistical |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2022.999319/full |
| work_keys_str_mv | AT markusjaschwanden interfaceregionimagingspectrographirisobservationsofthefractaldimensioninthesolaratmosphere AT nivedvilangotnhalil interfaceregionimagingspectrographirisobservationsofthefractaldimensioninthesolaratmosphere |