High frequency Raman current drive

Seppo Karttunen, Timo Pättikangas, Rainer Salomaa, Seppo Sipilä

Research output: Contribution to journalArticleScientificpeer-review

9 Citations (Scopus)

Abstract

Current drive in reactor grade tokamak plasmas with a pulsed, high power free electron laser (FEL) is investigated. The stimulated Raman process generates fast, longitudinal electron plasma waves which accelerate electrons to relativistic energies. The fast electrons with vi v are not trapped toroidally and the resulting current decays slowly. The paper presents a systematic study on different combinations of Raman forward and backward scattering and FEL polarization. The optimal FEL frequencies fall within the range 2.2-4.0ωp (left circularly polarized case) and 3.8-7.0ωp (right circularly polarized case) in a typical tokamak plasma with Ωe 1.5ωp In a reactor grade plasma the best current drive efficiency, 5 × 10l9 A/W⋅m2, is obtained by using the stimulated Raman forward process and a left circularly polarized FEL beam. The FEL driven current can be localized to the plasma centre and amplified by the bootstrap effect to further enhance the overall efficiency. Raman current drive in high temperature reactor plasmas is quite different from small scale experiments with Te ~ 1 keV, where the Raman backward process dominates and the current drive efficiency remains rather low.

Original languageEnglish
Pages (from-to)1079 - 1097
Number of pages19
JournalNuclear Fusion
Volume31
Issue number6
DOIs
Publication statusPublished - 1991
MoE publication typeA1 Journal article-refereed

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free electron lasers
reactors
grade
forward scattering
plasma waves
electron plasma
high power lasers
electrons
laser beams
electron beams
Raman spectra
decay
polarization
scattering
energy

Cite this

Karttunen, S., Pättikangas, T., Salomaa, R., & Sipilä, S. (1991). High frequency Raman current drive. Nuclear Fusion, 31(6), 1079 - 1097. https://doi.org/10.1088/0029-5515/31/6/006
Karttunen, Seppo ; Pättikangas, Timo ; Salomaa, Rainer ; Sipilä, Seppo. / High frequency Raman current drive. In: Nuclear Fusion. 1991 ; Vol. 31, No. 6. pp. 1079 - 1097.
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abstract = "Current drive in reactor grade tokamak plasmas with a pulsed, high power free electron laser (FEL) is investigated. The stimulated Raman process generates fast, longitudinal electron plasma waves which accelerate electrons to relativistic energies. The fast electrons with vi v⊥ are not trapped toroidally and the resulting current decays slowly. The paper presents a systematic study on different combinations of Raman forward and backward scattering and FEL polarization. The optimal FEL frequencies fall within the range 2.2-4.0ωp (left circularly polarized case) and 3.8-7.0ωp (right circularly polarized case) in a typical tokamak plasma with Ωe 1.5ωp In a reactor grade plasma the best current drive efficiency, 5 × 10l9 A/W⋅m2, is obtained by using the stimulated Raman forward process and a left circularly polarized FEL beam. The FEL driven current can be localized to the plasma centre and amplified by the bootstrap effect to further enhance the overall efficiency. Raman current drive in high temperature reactor plasmas is quite different from small scale experiments with Te ~ 1 keV, where the Raman backward process dominates and the current drive efficiency remains rather low.",
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Karttunen, S, Pättikangas, T, Salomaa, R & Sipilä, S 1991, 'High frequency Raman current drive', Nuclear Fusion, vol. 31, no. 6, pp. 1079 - 1097. https://doi.org/10.1088/0029-5515/31/6/006

High frequency Raman current drive. / Karttunen, Seppo; Pättikangas, Timo; Salomaa, Rainer; Sipilä, Seppo.

In: Nuclear Fusion, Vol. 31, No. 6, 1991, p. 1079 - 1097.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - High frequency Raman current drive

AU - Karttunen, Seppo

AU - Pättikangas, Timo

AU - Salomaa, Rainer

AU - Sipilä, Seppo

PY - 1991

Y1 - 1991

N2 - Current drive in reactor grade tokamak plasmas with a pulsed, high power free electron laser (FEL) is investigated. The stimulated Raman process generates fast, longitudinal electron plasma waves which accelerate electrons to relativistic energies. The fast electrons with vi v⊥ are not trapped toroidally and the resulting current decays slowly. The paper presents a systematic study on different combinations of Raman forward and backward scattering and FEL polarization. The optimal FEL frequencies fall within the range 2.2-4.0ωp (left circularly polarized case) and 3.8-7.0ωp (right circularly polarized case) in a typical tokamak plasma with Ωe 1.5ωp In a reactor grade plasma the best current drive efficiency, 5 × 10l9 A/W⋅m2, is obtained by using the stimulated Raman forward process and a left circularly polarized FEL beam. The FEL driven current can be localized to the plasma centre and amplified by the bootstrap effect to further enhance the overall efficiency. Raman current drive in high temperature reactor plasmas is quite different from small scale experiments with Te ~ 1 keV, where the Raman backward process dominates and the current drive efficiency remains rather low.

AB - Current drive in reactor grade tokamak plasmas with a pulsed, high power free electron laser (FEL) is investigated. The stimulated Raman process generates fast, longitudinal electron plasma waves which accelerate electrons to relativistic energies. The fast electrons with vi v⊥ are not trapped toroidally and the resulting current decays slowly. The paper presents a systematic study on different combinations of Raman forward and backward scattering and FEL polarization. The optimal FEL frequencies fall within the range 2.2-4.0ωp (left circularly polarized case) and 3.8-7.0ωp (right circularly polarized case) in a typical tokamak plasma with Ωe 1.5ωp In a reactor grade plasma the best current drive efficiency, 5 × 10l9 A/W⋅m2, is obtained by using the stimulated Raman forward process and a left circularly polarized FEL beam. The FEL driven current can be localized to the plasma centre and amplified by the bootstrap effect to further enhance the overall efficiency. Raman current drive in high temperature reactor plasmas is quite different from small scale experiments with Te ~ 1 keV, where the Raman backward process dominates and the current drive efficiency remains rather low.

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