Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas
We propose a method for reconstructing the fluctuation components of the electron velocity distribution function (EVDF), and the electron entropy, which is a functional of the fluctuation components of the EVDF, using the harmonic spectrum from pure X-mode electron cyclotron emission (ECE) in optica...
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IOP Publishing
2025-01-01
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| Series: | Nuclear Fusion |
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| Online Access: | https://doi.org/10.1088/1741-4326/ad9f81 |
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| author | Kawamori Eiichirou |
| author_facet | Kawamori Eiichirou |
| author_sort | Kawamori Eiichirou |
| collection | DOAJ |
| description | We propose a method for reconstructing the fluctuation components of the electron velocity distribution function (EVDF), and the electron entropy, which is a functional of the fluctuation components of the EVDF, using the harmonic spectrum from pure X-mode electron cyclotron emission (ECE) in optically thin plasmas. This formulation employs the maximum entropy method in velocity space using the Hankel transform, which converts from v _⊥ space to p space (where, v _⊥ and p are the electron velocity perpendicular to the background magnetic field and the index of the wavenumber in velocity space). Numerical tests validated the effectiveness of the proposed method, which is applicable across a wide range of magnetized plasma conditions, including conditions with both non-relativistic and relativistic electrons, except in cases of harmonic overlap or under optically thick conditions. Notably, this method does not require radiometer calibration for ECE measurements. This method facilitates the experimental evaluation of electron entropy transport in fusion plasma experiments. Moreover, when combined with measurements in k -space (spatial distribution), this approach enables entropy distribution acquisition in phase space ( k-p space). |
| format | Article |
| id | doaj-art-073c1699a83a40b78a658bd5c1ce2639 |
| institution | Kabale University |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Nuclear Fusion |
| spelling | doaj-art-073c1699a83a40b78a658bd5c1ce26392025-01-06T08:53:20ZengIOP PublishingNuclear Fusion0029-55152025-01-0165202602410.1088/1741-4326/ad9f81Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmasKawamori Eiichirou0https://orcid.org/0000-0001-7864-9924Institute of Space and Plasma Sciences, National Cheng Kung University , Tainan, TaiwanWe propose a method for reconstructing the fluctuation components of the electron velocity distribution function (EVDF), and the electron entropy, which is a functional of the fluctuation components of the EVDF, using the harmonic spectrum from pure X-mode electron cyclotron emission (ECE) in optically thin plasmas. This formulation employs the maximum entropy method in velocity space using the Hankel transform, which converts from v _⊥ space to p space (where, v _⊥ and p are the electron velocity perpendicular to the background magnetic field and the index of the wavenumber in velocity space). Numerical tests validated the effectiveness of the proposed method, which is applicable across a wide range of magnetized plasma conditions, including conditions with both non-relativistic and relativistic electrons, except in cases of harmonic overlap or under optically thick conditions. Notably, this method does not require radiometer calibration for ECE measurements. This method facilitates the experimental evaluation of electron entropy transport in fusion plasma experiments. Moreover, when combined with measurements in k -space (spatial distribution), this approach enables entropy distribution acquisition in phase space ( k-p space).https://doi.org/10.1088/1741-4326/ad9f81electron entropyharmonic electron cyclotron emissionphase space |
| spellingShingle | Kawamori Eiichirou Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas Nuclear Fusion electron entropy harmonic electron cyclotron emission phase space |
| title | Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas |
| title_full | Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas |
| title_fullStr | Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas |
| title_full_unstemmed | Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas |
| title_short | Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas |
| title_sort | reconstruction of electron velocity distribution function and gibbs entropy from electron cyclotron emission in magnetized plasmas |
| topic | electron entropy harmonic electron cyclotron emission phase space |
| url | https://doi.org/10.1088/1741-4326/ad9f81 |
| work_keys_str_mv | AT kawamorieiichirou reconstructionofelectronvelocitydistributionfunctionandgibbsentropyfromelectroncyclotronemissioninmagnetizedplasmas |