[P-EM17] 宇宙プラズマ科学

[PEM17-07] 高強度レーザーを用いたイオンの航跡場加速

*諌山 翔伍¹、中原 寛太¹、蔵満 康浩²、安部 勇輝²、南 卓海²、山ノ井 航平³、兼安 祐実³、福田 祐仁⁴、近藤 康太郎 ⁴、境 健太郎⁵、金崎 真聡⁹、田中 周太⁶、陳 仕宏⁷、劉 耀澧⁸ (1.九州大学総合理工学研究院、2.大阪大学大学院工学研究科、3.大阪大学レーザー科学研究所、4.量子科学技術研究開発機構、5.核融合科学研究所、6.青山学院大学物理科学科、7.台湾国立中央大学物理学科、8.国立成功大学宇宙プラズマ科学研究所、9.神戸大学大学院海事科学研究科)

キーワード：超高エネルギー宇宙線、航跡場加速、高強度レーザー

The acceleration mechanism of ultra-high-energy cosmic rays (UHECRs) remains an open question. Wakefield acceleration, where charged particles are accelerated by plasma waves, is considered a possible mechanism, as it enables efficient energy gain with minimal radiation loss. While wakefield acceleration has been extensively studied for electrons, experimental verification of ion wakefield acceleration remains limited due to the high phase velocity of plasma waves in conventional conditions. In this study, we investigate ion wakefield acceleration using the J-KAREN-P laser system. Our experiment employs a foam target with a near-critical density (~5n_c) to reduce the phase velocity of the plasma wave, enabling ion trapping and acceleration.
Preliminary results from our experiment indicate the successful acceleration of protons and carbon ions through wakefield mechanism. These findings provide a crucial step toward reproducing ion wakefield acceleration under laboratory conditions, offering insights into the mechanisms underlying cosmic-ray acceleration. Future experiments aim to achieve relativistic ion energies, further bridging the gap between laboratory plasma physics and astrophysical phenomena.
In this presentation, we will discuss the initial experimental results obtained in December 2022 and explore potential strategies for achieving higher ion energies, supported by numerical simulations.