Research on high energy density plasmas produced by peta watt laser

2003年，我们启动了这项计划，在五年内开创了Peta瓦激光等离子体研究的新领域。在实验方面，由于引入了新的OPCPA前端，将预脉冲级从10^~(-4)降低到10^~(-8)，改进的GMII已应用于质子加速。通过使用薄的箔靶，我们实现了高达20 MeV的加速。我们还对固体平板靶进行了辐照，测量了相对论电子能谱，其斜率温度在没有预脉冲的情况下低于有预脉冲的情况。在理论和模拟研究方面，我们将辐射流体力学模拟与HELO程序、集体PIC模拟和福克-普朗克模拟相结合，对激光聚变和中子源研究中的快速等离子体加热进行了模拟。作为…快速点火实验的目标设计在FI3的作用下，模拟了锥形靶实验中的内爆等离子体加热过程。特别是引入了双锥靶来改善锥体中的相对论电子约束，并将其引导到锥体的尖端。PIC模拟表明，真空带隙中产生的强磁场对相对论电子有较长时间的限制。结果表明，耦合效率提高了1.5倍。我们还研究了预等离子体对高能电子输运的影响。研究发现，当预等离子体的标尺长度超过几μm时，电子斜率温度过高，不利于等离子体的有效加热。为了克服这一困难，我们利用预脉冲对等离子体产生过程进行了研究。根据模拟结果，预脉冲强度要求小于10；lt；11；W/cm2。最后，经过5年的项目研究，开发了完整的模拟程序，并进行了验证。仿真研究为实验设计和分析做出了贡献。在实验中，对GMII短脉冲超强激光器进行了改进，并将其应用于质子和电子束加速实验。阐明了S的自生磁场和相对论电子导引。较少

In 2003, we started this project to create a new field in the research of peta watt laser plasmas within five years. As for the experiments, since the new OPCPA front end was introduced to reduce the pre-pulse level from 10^<-4> to 10^<-8>, the improved GMII has been applied to the proton acceleration. By using a thin foil target, we achieved the acceleration of up to about 20MeV. We also irradiated solid planer targets to measure the relativistic electron spectrum of which slope temperature without pre-pulse is lower than that with pre-pulse. By this achievement, we can carry out well controlled experiments and analyze experimental data precisely with theory and simulation.In the theory and simulation research, we combined a radiation hydrodynamic simulation with the hydro code PINOCO, a collective PIC simulation, and a Fokker Planck simulation to simulate the fast plasma heating for laser fusion and neutron source researches. As the target design for the fast ignition experiments wit … More h of FI3, we simulated the imploded plasma heating processes for the cone target experiment. In particular, the double cone target was introduced to improve the relativistic electron confinement in the cone and guiding them to he tip of the cone. The PIC simulation indicated that the strong magnetic fields in the vacuum gap are generated which confine relativistic electrons for a long time. As the results, the coupling efficiency is enhanced by 1.5 time. We also investigated the pre-plasma effects on the high energy electron transport. It is found that when the scale length of the pre-plasma exceeds a few μm, the electron slope temperature is too hig for the efficient plasma heating. In order to overcome this difficulty, we investigated the plasma production processes by the pre-pulse. According to the simulations, prepulse intensity is required to be lower than 10^<11>W/cm^2.In conclusion, after 5 year project, the integrated simulation code was developed and validated. The simulation research contributed to the experiment design and analysis. In the experiment, the GMII short pulse ultra intense laser was improved and applied to the proton and electron beam acceleration experiments. The self-generated magnetic field s and the relativistic electron guiding have been clarified. Less