Suppression of parametric instabilities in inhomogeneous plasma with multi-frequency light

Yao Zhao, Suming Weng, Zhengming Sheng, Jianqiang Zhu

Research output: Contribution to journalArticle

Abstract

The development of parametric instabilities in a large scale inhomogeneous plasma with an incident laser beam composed of multiple frequency components is studied theoretically and numerically. Firstly, theoretical analyses of the coupling between two laser beamlets with certain frequency difference δω 0 for parametric instabilities is presented. It suggests that the two beamlets will be decoupled when δω 0 is larger than certain thresholds, which are derived for stimulated Raman scattering, stimulated Brillouin scattering, and two plasmon decay, respectively. In this case, the parametric instabilities for the two beamlets develop independently and can be controlled at a low level provided the laser intensity for individual beamlet is low enough. Secondly, numerical simulations of parametric instabilities with two or more beamlets (N ∼ 20) have been carried out and the above theory model is validated. Simulations confirm that the development of parametric instabilities with multiple beamlets can be controlled at a low level, provided the threshold conditions for δω 0 is satisfied, even though the total laser intensity is as high as ∼10 15 W cm -2. With such a laser beam structure of multiple frequency components and total bandwidth of a few percentages (⪆4%ω 0), the parametric instabilities can be well-controlled.

LanguageEnglish
Article number115008
Number of pages8
JournalPlasma Physics and Controlled Fusion
Volume61
Issue number11
DOIs
Publication statusPublished - 7 Oct 2019

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Plasma stability
retarding
Plasmas
Laser beams
Lasers
Stimulated Raman scattering
Stimulated Brillouin scattering
laser beams
lasers
thresholds
Bandwidth
simulation
Raman spectra
bandwidth
Computer simulation
decay
scattering

Keywords

  • parametric instabilities
  • inhomogeneous plasma
  • laser beamlets
  • laser plasma instabilities

Cite this

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title = "Suppression of parametric instabilities in inhomogeneous plasma with multi-frequency light",
abstract = "The development of parametric instabilities in a large scale inhomogeneous plasma with an incident laser beam composed of multiple frequency components is studied theoretically and numerically. Firstly, theoretical analyses of the coupling between two laser beamlets with certain frequency difference δω 0 for parametric instabilities is presented. It suggests that the two beamlets will be decoupled when δω 0 is larger than certain thresholds, which are derived for stimulated Raman scattering, stimulated Brillouin scattering, and two plasmon decay, respectively. In this case, the parametric instabilities for the two beamlets develop independently and can be controlled at a low level provided the laser intensity for individual beamlet is low enough. Secondly, numerical simulations of parametric instabilities with two or more beamlets (N ∼ 20) have been carried out and the above theory model is validated. Simulations confirm that the development of parametric instabilities with multiple beamlets can be controlled at a low level, provided the threshold conditions for δω 0 is satisfied, even though the total laser intensity is as high as ∼10 15 W cm -2. With such a laser beam structure of multiple frequency components and total bandwidth of a few percentages (⪆4{\%}ω 0), the parametric instabilities can be well-controlled.",
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author = "Yao Zhao and Suming Weng and Zhengming Sheng and Jianqiang Zhu",
year = "2019",
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doi = "10.1088/1361-6587/ab4691",
language = "English",
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journal = "Plasma Physics and Controlled Fusion",
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Suppression of parametric instabilities in inhomogeneous plasma with multi-frequency light. / Zhao, Yao; Weng, Suming; Sheng, Zhengming; Zhu, Jianqiang.

In: Plasma Physics and Controlled Fusion, Vol. 61, No. 11, 115008, 07.10.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Suppression of parametric instabilities in inhomogeneous plasma with multi-frequency light

AU - Zhao, Yao

AU - Weng, Suming

AU - Sheng, Zhengming

AU - Zhu, Jianqiang

PY - 2019/10/7

Y1 - 2019/10/7

N2 - The development of parametric instabilities in a large scale inhomogeneous plasma with an incident laser beam composed of multiple frequency components is studied theoretically and numerically. Firstly, theoretical analyses of the coupling between two laser beamlets with certain frequency difference δω 0 for parametric instabilities is presented. It suggests that the two beamlets will be decoupled when δω 0 is larger than certain thresholds, which are derived for stimulated Raman scattering, stimulated Brillouin scattering, and two plasmon decay, respectively. In this case, the parametric instabilities for the two beamlets develop independently and can be controlled at a low level provided the laser intensity for individual beamlet is low enough. Secondly, numerical simulations of parametric instabilities with two or more beamlets (N ∼ 20) have been carried out and the above theory model is validated. Simulations confirm that the development of parametric instabilities with multiple beamlets can be controlled at a low level, provided the threshold conditions for δω 0 is satisfied, even though the total laser intensity is as high as ∼10 15 W cm -2. With such a laser beam structure of multiple frequency components and total bandwidth of a few percentages (⪆4%ω 0), the parametric instabilities can be well-controlled.

AB - The development of parametric instabilities in a large scale inhomogeneous plasma with an incident laser beam composed of multiple frequency components is studied theoretically and numerically. Firstly, theoretical analyses of the coupling between two laser beamlets with certain frequency difference δω 0 for parametric instabilities is presented. It suggests that the two beamlets will be decoupled when δω 0 is larger than certain thresholds, which are derived for stimulated Raman scattering, stimulated Brillouin scattering, and two plasmon decay, respectively. In this case, the parametric instabilities for the two beamlets develop independently and can be controlled at a low level provided the laser intensity for individual beamlet is low enough. Secondly, numerical simulations of parametric instabilities with two or more beamlets (N ∼ 20) have been carried out and the above theory model is validated. Simulations confirm that the development of parametric instabilities with multiple beamlets can be controlled at a low level, provided the threshold conditions for δω 0 is satisfied, even though the total laser intensity is as high as ∼10 15 W cm -2. With such a laser beam structure of multiple frequency components and total bandwidth of a few percentages (⪆4%ω 0), the parametric instabilities can be well-controlled.

KW - parametric instabilities

KW - inhomogeneous plasma

KW - laser beamlets

KW - laser plasma instabilities

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DO - 10.1088/1361-6587/ab4691

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JO - Plasma Physics and Controlled Fusion

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