A Scenario for Origin of Global 4 mHz Oscillations in Solar Corona
We establish a spherically symmetric model of solar atmosphere, which consists of the whole chromosphere and low corona below the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.25</mn>&l...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Universe |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2218-1997/11/1/14 |
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| Summary: | We establish a spherically symmetric model of solar atmosphere, which consists of the whole chromosphere and low corona below the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.25</mn></mrow></semantics></math></inline-formula> solar radius. It is a hydrodynamic model with heating in the chromosphere through an artificial energy flux. We performed a series of simulations with our model and found oscillations with a peak frequency of ∼4 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>mHz</mi></semantics></math></inline-formula> in the power spectrum. We confirmed that this resulted from the <i>p</i>-mode excited in the transition region and amplified in a resonant cavity situated in the height range ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>4</mn><mo>×</mo><msup><mn>10</mn><mn>3</mn></msup></mrow></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup></mrow></semantics></math></inline-formula> km. This result is consistent with global observations of Alfvénic waves in corona and can naturally explain the observational ubiquity of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>4</mn><mspace width="2pt"></mspace><mi>mHz</mi></mrow></semantics></math></inline-formula> without the difficulty of the <i>p</i>-mode passing through the acoustic-damping chromosphere. We also confirmed that acoustic shock waves alone cannot heat the corona to the observed temperature, and found mass upflows in the height range ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>7</mn><mo>×</mo><msup><mn>10</mn><mn>3</mn></msup></mrow></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>7</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup></mrow></semantics></math></inline-formula> km in our model, which pumped the dense and cool plasma into the corona and might be the mass supplier for solar prominences. |
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| ISSN: | 2218-1997 |