| Project/Area Number |
18K13522
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 14010:Fundamental plasma-related
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| Research Institution | National Institutes for Quantum and Radiological Science and Technology (2019)
Kyoto University (2018) |
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Principal Investigator |
Kojima Sadaoki 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 研究員(任常) (40815156)
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| Project Period (FY) |
2018-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | レーザープラズマ相互作用 / 高強度レーザー / レーザーホールボーリング / 光圧 / レーザーイオン加速 / 相対論的電子 / プラズマ |
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| Outline of Final Research Achievements |
The dependence of the mean kinetic energy of laser-accelerated relativistic electrons (REs) on the laser intensity, so-called ponderomotive scaling, explains well the experimental results to date; however, this scaling is no longer applicable to multi-picosecond (multi-ps) laser experiments. Here, the production of REs was experimentally investigated via multi-ps relativistic laser–plasma-interaction (LPI). The lower slope temperature shows little dependence on the pulse duration and is close to the ponderomotive scaling value, while the higher slope temperature appears to be affected by the pulse duration. The higher slope temperature is far beyond the ponderomotive scaling value, which indicates super-ponderomotive REs (SP-REs). Simulation and experimental evidence are provided to indicate that the SP-REs are produced by LPI in an under-critical plasma, where a large quasi-static electromagnetic field grows rapidly after a threshold timing during multi-ps LPI.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で用いたLFEXレーザーは、2018年にノーベル物理学賞を受賞したチャープパルス増幅法を利用し、地上で最も眩しい光を発射する実験装置の一つです。本研究ではこの高強度レーザーを物質に照射し続けることで、プラズマ中にキロ・テスラ3級の磁場を突発的に発生させ、レーザーによる電子加速の効率を4倍以上に増大させることに成功しました。本研究は、レーザー核融合エネルギーの実現に貢献すると共に、小型医療用粒子線加速器などへの応用も期待されます。
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