Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks
Turbulence and transport phenomena play a crucial role in the confinement and stability of tokamak plasmas. Turbulent fluctuations in certain physical quantities, such as density or temperature fluctuations, can have a wide range of spatial scales, and understanding their correlation length is impor...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-07-01
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| Series: | Plasma |
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| Online Access: | https://www.mdpi.com/2571-6182/6/3/31 |
| _version_ | 1797577734457655296 |
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| author | Jan Weiland Tariq Rafiq Eugenio Schuster |
| author_facet | Jan Weiland Tariq Rafiq Eugenio Schuster |
| author_sort | Jan Weiland |
| collection | DOAJ |
| description | Turbulence and transport phenomena play a crucial role in the confinement and stability of tokamak plasmas. Turbulent fluctuations in certain physical quantities, such as density or temperature fluctuations, can have a wide range of spatial scales, and understanding their correlation length is important for predicting and controlling the behavior of the plasma. The correlation length in the radial direction is identified as the critical length in real space. The dynamics in real space are of significant interest because transport in configuration space is primarily focused on them. When investigating transport caused by the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="bold">E</mi><mo>×</mo><mi mathvariant="bold">B</mi></mrow></semantics></math></inline-formula> drift, the correlation length in real space represents the size of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="bold">E</mi><mo>×</mo><mi mathvariant="bold">B</mi></mrow></semantics></math></inline-formula> whirls. It was numerically discovered that in drift wave turbulence, this length is inversely proportional to the normalized mode number of the fastest growing mode relative to the drift frequency. Considerable time was required before a proper analytical derivation of this condition was accomplished. Therefore, a connection has been established between phenomena occurring in real space and those occurring in k-space. Although accompanied by a turbulent spectrum in k-space with a substantial width, transport in real space is uniquely determined by the correlation length, allowing for accurate transport calculations through the dynamics of a single mode. Naturally, the dynamics are subject to nonlinear effects, with resonance broadening in frequency being the most significant nonlinear effect. Thus, mode number space is once again involved. Resonance broadening leads to the detuning of waves from particles, permitting a fluid treatment. It should be emphasized that the consideration here involves the total electric field, including the induction part, which becomes particularly important at higher beta plasmas. |
| first_indexed | 2024-03-10T22:12:11Z |
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| id | doaj.art-3cdf03a8a6cb450da36abc43f0824c57 |
| institution | Directory Open Access Journal |
| issn | 2571-6182 |
| language | English |
| last_indexed | 2024-03-10T22:12:11Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Plasma |
| spelling | doaj.art-3cdf03a8a6cb450da36abc43f0824c572023-11-19T12:33:38ZengMDPI AGPlasma2571-61822023-07-016345946510.3390/plasma6030031Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in TokamaksJan Weiland0Tariq Rafiq1Eugenio Schuster2Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18017, USADepartment of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18017, USADepartment of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18017, USATurbulence and transport phenomena play a crucial role in the confinement and stability of tokamak plasmas. Turbulent fluctuations in certain physical quantities, such as density or temperature fluctuations, can have a wide range of spatial scales, and understanding their correlation length is important for predicting and controlling the behavior of the plasma. The correlation length in the radial direction is identified as the critical length in real space. The dynamics in real space are of significant interest because transport in configuration space is primarily focused on them. When investigating transport caused by the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="bold">E</mi><mo>×</mo><mi mathvariant="bold">B</mi></mrow></semantics></math></inline-formula> drift, the correlation length in real space represents the size of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="bold">E</mi><mo>×</mo><mi mathvariant="bold">B</mi></mrow></semantics></math></inline-formula> whirls. It was numerically discovered that in drift wave turbulence, this length is inversely proportional to the normalized mode number of the fastest growing mode relative to the drift frequency. Considerable time was required before a proper analytical derivation of this condition was accomplished. Therefore, a connection has been established between phenomena occurring in real space and those occurring in k-space. Although accompanied by a turbulent spectrum in k-space with a substantial width, transport in real space is uniquely determined by the correlation length, allowing for accurate transport calculations through the dynamics of a single mode. Naturally, the dynamics are subject to nonlinear effects, with resonance broadening in frequency being the most significant nonlinear effect. Thus, mode number space is once again involved. Resonance broadening leads to the detuning of waves from particles, permitting a fluid treatment. It should be emphasized that the consideration here involves the total electric field, including the induction part, which becomes particularly important at higher beta plasmas.https://www.mdpi.com/2571-6182/6/3/31turbulence and transport modelingmagnetic confinementcorrelation lengthresonance broadeningtokamaksdrift waves |
| spellingShingle | Jan Weiland Tariq Rafiq Eugenio Schuster Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks Plasma turbulence and transport modeling magnetic confinement correlation length resonance broadening tokamaks drift waves |
| title | Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks |
| title_full | Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks |
| title_fullStr | Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks |
| title_full_unstemmed | Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks |
| title_short | Unveiling the Significance of Correlations in K-Space and Configuration Space for Drift Wave Turbulence in Tokamaks |
| title_sort | unveiling the significance of correlations in k space and configuration space for drift wave turbulence in tokamaks |
| topic | turbulence and transport modeling magnetic confinement correlation length resonance broadening tokamaks drift waves |
| url | https://www.mdpi.com/2571-6182/6/3/31 |
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