发表机构
State Key Laboratory of Nuclear Physics and Technology, and Key Laboratory of HEDP of the Ministry of Education, CAPT, School of Physics, Peking University; Institute of Theoretical Physics, Chinese Academy of Sciences; Institute of Modern Physics, Fudan University; Beijing Laser Acceleration Innovation Center（北京大学物理学院; 中国科学院理论物理研究所; 复旦大学现代物理研究所; 北京激光加速创新中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出理论模型，通过解析激光驱动等离子体通道中磁岛形成的临界条件与标度律，并经大规模粒子模拟验证，将磁岛几何从定性特征变为可预测量，为粒子加速和聚变点火等应用奠定基础。
AI 中文摘要
我们为近临界密度等离子体中相对论激光驱动通道内自生磁岛建立了一个理论模型。这些磁岛源于由纵向通道电流 $j_x$ 和激光前沿驱动的横向电流 $j_y$ 所产生的准静态磁场的非线性叠加。通过推导激光耗尽、横向对称通道形成和磁岛形成之间的临界条件，我们确定了磁岛结构可以存在的激光-等离子体参数窗口。在此窗口内，激光有质动力与电荷分离力之间的平衡（通过有效电子密度 $n_\mathrm{eff}$ 表达）决定了横向岛宽度 $H$，而激光群速度与相速度之间的失配则决定了纵向周期 $L$。在广泛的激光强度和等离子体密度范围内进行的大规模粒子网格模拟验证了所得标度律。该模型将岛的几何形状从通道场的定性特征转变为可预测的量，为在相对论激光-等离子体相互作用中调控电子输运、粒子加速、高能辐射以及新型聚变点火方案提供了基础。
英文摘要
We develop a theoretical model for self-generated magnetic islands in relativistic laser-driven channels in near-critical-density plasmas. The islands arise from the nonlinear superposition of the quasi-static magnetic fields generated by the longitudinal channel current $j_x$ and the laser-front driven transverse current $j_y$. By deriving the critical conditions among laser depletion, transversely symmetric channel formation, and magnetic-island formation, we identify the laser-plasma parameter window in which the magnetic island structures can exist. Within this window, the balance between the laser ponderomotive force and the charge-separation force, expressed through an effec tive electron density $n_\mathrm{eff}$, determines the transverse island width $H$, whereas the mismatch between the laser group and phase velocities determines the longitudinal period $L$. Large-scale particle-in-cell simulations over a broad range of laser intensities and plasma densities validate the resulting scaling laws. The model turns the island geometry from a qualitative feature of the channel field into a predictable quantity, providing a basis for tailoring electron transport, particle acceleration, high-energy radiation, and novel fusion ignition schemes in relativistic laser-plasma interactions.
