Laser Plasma Interactions in MegaGauss Magnetic Fields

宇宙中的恒星、星系和星云都是由等离子体状态的物质组成的。磁场极大地影响等离子体的特性。磁场被认为是灾难性宇宙事件的原因，比如恒星坍缩产生的超强x射线爆发和太阳耀斑的爆炸。了解强磁场中的等离子体对天体物理学、基础等离子体物理学以及能源和国防应用具有重要意义。内华达大学里诺分校（University of Nevada, Reno）将兆安培电流发生器和强大的短脉冲激光器独特地结合在一起，可以在比地球磁场强数百万倍的磁场中研究等离子体。本项目将研究强磁场对固体靶中强激光产生的高能电子束和质子束的影响。与罗切斯特大学合作，三名研究生将接受培训，并将进行实验和理论工作。在1 ~ 1.5 MGauss的轴向磁场下，研究固体激光靶中的电子输运。脉冲电源发生器提供了良好的测量和控制磁场。目标背面的相干瞬态辐射将照亮电子束的一个点，并在磁场中显示引导和聚焦效应。本文将采用相同的实验配置，结合激光和脉冲功率能力，研究外磁场中质子束的增强产生。“原理验证”实验将在~1.5 MGauss的磁场下进行。实验计划将通过使用混合粒子-细胞编码在强纵向磁场中模拟电子和质子束来支持。该项目的结果与惯性约束聚变的“快速点火”方法和医疗应用有关。该项目由物理系和促进竞争性研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Stars, galaxies, and nebulae in the universe consist of matter in a plasma state. Magnetic fields dramatically impact properties of plasma. Magnetic fields are thought to be responsible for catastrophic cosmic events such as generation of super-strong x-ray bursts by collapsing stars and explosion of solar flares. Understanding of plasma in strong magnetic fields is important for astrophysics, basic plasma physics, and energy and national defense applications. A unique combination of the Mega-Ampere current generator and powerful short-pulse laser at the University of Nevada, Reno allows to investigate plasmas in magnetic fields that are millions of times stronger that the Earth's magnetic field. In this project, the impact of strong magnetic fields on high-energy beams of electrons, and proton beams generated by the powerful laser in a solid target will be studied. In collaboration with the University of Rochester, three graduate students will be trained and will perform experimental and theoretical work.Electron transport in the solid laser target will be studied in the axial magnetic field of 1-1.5 MGauss. The pulsed power generator provides well measured and controlled magnetic fields. Coherent transient radiation from the rear side of the target will illuminate a spot of the electron beam and indicate a guiding and focusing effect in the magnetic field. Enhanced generation of proton beams in the external magnetic field will be studied with the same experimental configuration combining laser and pulsed power capabilities. A "proof of principle" experiment will be performed at the magnetic field of ~1.5 MGauss. The experimental program will be supported by simulations of electron and proton beams in a strong longitudinal magnetic field using hybrid particle-in-cell codes. Results of the project are relevant to the "fast ignition" approach to inertial confinement fusion and for medical applications. This project is jointly funded by the Division of Physics and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.