Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements
The intensity ratio of Fe XIV 264.765A/274.203A is useful to determine the electron density of solar corona, and the relationship between the electron density and the intensity ratio obtained from a model should be evaluated using laboratory plasmas to estimate the electron density more precisely. W...
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MDPI AG
2021-08-01
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| author | Nagaaki Kambara Tomoko Kawate Tetsutarou Oishi Yasuko Kawamoto Hiroyuki A. Sakaue Daiji Kato Nobuyuki Nakamura Hirohisa Hara Izumi Murakami |
| author_facet | Nagaaki Kambara Tomoko Kawate Tetsutarou Oishi Yasuko Kawamoto Hiroyuki A. Sakaue Daiji Kato Nobuyuki Nakamura Hirohisa Hara Izumi Murakami |
| author_sort | Nagaaki Kambara |
| collection | DOAJ |
| description | The intensity ratio of Fe XIV 264.765A/274.203A is useful to determine the electron density of solar corona, and the relationship between the electron density and the intensity ratio obtained from a model should be evaluated using laboratory plasmas to estimate the electron density more precisely. We constructed a new collisional–radiative model (CR-model) for Fe XIV (an Al-like iron ion) by considering the processes of proton-impact excitation and electron-impact ionization to the excited states of a Mg-like iron ion. The atomic data used in the CR-model were calculated using the HULLAC atomic code. The model was evaluated based on laboratory experiments using a compact electron beam ion trap, called CoBIT, and the Large Helical Device (LHD). The measured Fe XIV 264.785 Å/274.203 Å line intensity ratio with CoBIT was 1.869 ± 0.036, and it agreed well with our CR-model results. Concurrently, the measured ratio using LHD was larger than the results of our CR-model and CHIANTI. The estimated electron densities using our CR-model agreed with those from CHIANTI within a factor of 1.6–2.4 in the range of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>n</mi><mi>e</mi></msub><mo>≈</mo><msup><mn>10</mn><mrow><mn>10</mn><mo>−</mo><mn>11</mn></mrow></msup><mspace width="3.33333pt"></mspace><msup><mi>cm</mi><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></semantics></math></inline-formula>. Further model development is needed to explain the ratio in a high-electron density region. |
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| issn | 2218-2004 |
| language | English |
| last_indexed | 2024-03-10T07:54:04Z |
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| spelling | doaj.art-4af35316cb8c4419850b19e9d19cc7612023-11-22T12:01:33ZengMDPI AGAtoms2218-20042021-08-01936010.3390/atoms9030060Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory MeasurementsNagaaki Kambara0Tomoko Kawate1Tetsutarou Oishi2Yasuko Kawamoto3Hiroyuki A. Sakaue4Daiji Kato5Nobuyuki Nakamura6Hirohisa Hara7Izumi Murakami8Department of Astronomical Science, The Graduate University for Advanced Studies, SOKENDAI, Mitaka, Tokyo 181-8588, JapanNational Institute for Fusion Science, Toki, Gifu 509-5292, JapanNational Institute for Fusion Science, Toki, Gifu 509-5292, JapanNational Institute for Fusion Science, Toki, Gifu 509-5292, JapanNational Institute for Fusion Science, Toki, Gifu 509-5292, JapanNational Institute for Fusion Science, Toki, Gifu 509-5292, JapanInstitute for Laser Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, JapanNational Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, JapanNational Institute for Fusion Science, Toki, Gifu 509-5292, JapanThe intensity ratio of Fe XIV 264.765A/274.203A is useful to determine the electron density of solar corona, and the relationship between the electron density and the intensity ratio obtained from a model should be evaluated using laboratory plasmas to estimate the electron density more precisely. We constructed a new collisional–radiative model (CR-model) for Fe XIV (an Al-like iron ion) by considering the processes of proton-impact excitation and electron-impact ionization to the excited states of a Mg-like iron ion. The atomic data used in the CR-model were calculated using the HULLAC atomic code. The model was evaluated based on laboratory experiments using a compact electron beam ion trap, called CoBIT, and the Large Helical Device (LHD). The measured Fe XIV 264.785 Å/274.203 Å line intensity ratio with CoBIT was 1.869 ± 0.036, and it agreed well with our CR-model results. Concurrently, the measured ratio using LHD was larger than the results of our CR-model and CHIANTI. The estimated electron densities using our CR-model agreed with those from CHIANTI within a factor of 1.6–2.4 in the range of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>n</mi><mi>e</mi></msub><mo>≈</mo><msup><mn>10</mn><mrow><mn>10</mn><mo>−</mo><mn>11</mn></mrow></msup><mspace width="3.33333pt"></mspace><msup><mi>cm</mi><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></semantics></math></inline-formula>. Further model development is needed to explain the ratio in a high-electron density region.https://www.mdpi.com/2218-2004/9/3/60EUV spectroscopyionized gaselectron density diagnosticscollisional–radiative modelLHDEBIT |
| spellingShingle | Nagaaki Kambara Tomoko Kawate Tetsutarou Oishi Yasuko Kawamoto Hiroyuki A. Sakaue Daiji Kato Nobuyuki Nakamura Hirohisa Hara Izumi Murakami Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements Atoms EUV spectroscopy ionized gas electron density diagnostics collisional–radiative model LHD EBIT |
| title | Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements |
| title_full | Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements |
| title_fullStr | Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements |
| title_full_unstemmed | Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements |
| title_short | Evaluation of Fe XIV Intensity Ratio for Electron Density Diagnostics by Laboratory Measurements |
| title_sort | evaluation of fe xiv intensity ratio for electron density diagnostics by laboratory measurements |
| topic | EUV spectroscopy ionized gas electron density diagnostics collisional–radiative model LHD EBIT |
| url | https://www.mdpi.com/2218-2004/9/3/60 |
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