X. F. Li, S. M. Weng, P. Gibbon, H. H. Ma, S. H. Yew, Z. Liu, Y. Zhao, M. Chen, Z. M. Sheng, J. Zhang
{"title":"等离子体中宽带激光从向后到侧向受激拉曼散射的转变","authors":"X. F. Li, S. M. Weng, P. Gibbon, H. H. Ma, S. H. Yew, Z. Liu, Y. Zhao, M. Chen, Z. M. Sheng, J. Zhang","doi":"10.1063/5.0152668","DOIUrl":null,"url":null,"abstract":"Broadband lasers have been proposed as future drivers of inertial confined fusion (ICF) to enhance the laser–target coupling efficiency via the mitigation of various parametric instabilities. The physical mechanisms involved have been explored recently, but are not yet fully understood. Here, stimulated Raman scattering (SRS) as one of the key parametric instabilities is investigated theoretically and numerically for a broadband laser propagating in homogeneous plasma in multidimensional geometry. The linear SRS growth rate is derived as a function of scattering angles for two monochromatic laser beams with a fixed frequency difference δω. If δω/ω0 ∼ 1%, with ω0 the laser frequency, these two laser beams may be decoupled in stimulating backward SRS while remaining coupled for sideward SRS at the laser intensities typical for ICF. Consequently, side-scattering may dominate over backward SRS for two-color laser light. This finding of SRS transition from backward to sideward SRS is then generalized for a broadband laser with a few-percent bandwidth. Particle-in-cell simulations demonstrate that with increasing laser bandwidth, the sideward SRS gradually becomes dominant over the backward SRS. Since sideward SRS is very efficient in producing harmful hot electrons, attention needs to be paid on this effect if ultra-broadband lasers are considered as next-generation ICF drivers.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"36 1","pages":"0"},"PeriodicalIF":4.8000,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Transition from backward to sideward stimulated Raman scattering with broadband lasers in plasmas\",\"authors\":\"X. F. Li, S. M. Weng, P. Gibbon, H. H. Ma, S. H. Yew, Z. Liu, Y. Zhao, M. Chen, Z. M. Sheng, J. Zhang\",\"doi\":\"10.1063/5.0152668\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Broadband lasers have been proposed as future drivers of inertial confined fusion (ICF) to enhance the laser–target coupling efficiency via the mitigation of various parametric instabilities. The physical mechanisms involved have been explored recently, but are not yet fully understood. Here, stimulated Raman scattering (SRS) as one of the key parametric instabilities is investigated theoretically and numerically for a broadband laser propagating in homogeneous plasma in multidimensional geometry. The linear SRS growth rate is derived as a function of scattering angles for two monochromatic laser beams with a fixed frequency difference δω. If δω/ω0 ∼ 1%, with ω0 the laser frequency, these two laser beams may be decoupled in stimulating backward SRS while remaining coupled for sideward SRS at the laser intensities typical for ICF. Consequently, side-scattering may dominate over backward SRS for two-color laser light. This finding of SRS transition from backward to sideward SRS is then generalized for a broadband laser with a few-percent bandwidth. Particle-in-cell simulations demonstrate that with increasing laser bandwidth, the sideward SRS gradually becomes dominant over the backward SRS. Since sideward SRS is very efficient in producing harmful hot electrons, attention needs to be paid on this effect if ultra-broadband lasers are considered as next-generation ICF drivers.\",\"PeriodicalId\":54221,\"journal\":{\"name\":\"Matter and Radiation at Extremes\",\"volume\":\"36 1\",\"pages\":\"0\"},\"PeriodicalIF\":4.8000,\"publicationDate\":\"2023-09-13\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Matter and Radiation at Extremes\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1063/5.0152668\",\"RegionNum\":1,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Matter and Radiation at Extremes","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1063/5.0152668","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
Transition from backward to sideward stimulated Raman scattering with broadband lasers in plasmas
Broadband lasers have been proposed as future drivers of inertial confined fusion (ICF) to enhance the laser–target coupling efficiency via the mitigation of various parametric instabilities. The physical mechanisms involved have been explored recently, but are not yet fully understood. Here, stimulated Raman scattering (SRS) as one of the key parametric instabilities is investigated theoretically and numerically for a broadband laser propagating in homogeneous plasma in multidimensional geometry. The linear SRS growth rate is derived as a function of scattering angles for two monochromatic laser beams with a fixed frequency difference δω. If δω/ω0 ∼ 1%, with ω0 the laser frequency, these two laser beams may be decoupled in stimulating backward SRS while remaining coupled for sideward SRS at the laser intensities typical for ICF. Consequently, side-scattering may dominate over backward SRS for two-color laser light. This finding of SRS transition from backward to sideward SRS is then generalized for a broadband laser with a few-percent bandwidth. Particle-in-cell simulations demonstrate that with increasing laser bandwidth, the sideward SRS gradually becomes dominant over the backward SRS. Since sideward SRS is very efficient in producing harmful hot electrons, attention needs to be paid on this effect if ultra-broadband lasers are considered as next-generation ICF drivers.
期刊介绍:
Matter and Radiation at Extremes (MRE), is committed to the publication of original and impactful research and review papers that address extreme states of matter and radiation, and the associated science and technology that are employed to produce and diagnose these conditions in the laboratory. Drivers, targets and diagnostics are included along with related numerical simulation and computational methods. It aims to provide a peer-reviewed platform for the international physics community and promote worldwide dissemination of the latest and impactful research in related fields.