Theoretical model of quasi static magnetic field generation and energy transport in the relativisitic laser-plasma interactions

相对论性激光脉冲与固体密度等离子体相互作用时，在过密等离子体表面产生强准静态磁场。沿表面的磁场抑制电子向等离子体的传播。我们研究了磁场的产生和激光到等离子体的能量输运机制。为了研究等离子体表面的磁场产生和激光吸收，我们开发了一维和二维完全相对论性的电磁粒子池（PIC）模拟代码。我们提出了磁场产生的理论模型。由相对论性激光脉冲产生的高能电子被固体密度中的高能电子和体电子所维持的准静态磁场所捕获。通过PIC仿真，对理论模型进行了验证。结果，正如理论模型所示，几乎高能电子被自感应磁场捕获。一些能量大于临界能量的电子穿过表面，这取决于内部激光强度和内部角度。电子电流在靶材的内等离子体和后表面产生准静态磁场。提出了强激光等离子体相互作用的热电子温度和电子能谱的标度，并用PIC模拟验证了标度的正确性。

Strong quasistatic magnetic fields at the surface of overdense plasmas are generated during the interaction of a relativistic laser pulse with solid density plasmas. The magnetic fields along the suface inhibit the propagetion of electrons into the plasma. We study the mechanisms of the magnetic field generation and the energy transport from the laser light to the plasma.In order to investigate the magnetic field generation and laser light absorption at the plasma surface we developed one- and two-dimensional fully relativistic electromagnetic particle-in-cell (PIC) simulatiuon codes. We propose a theoretical model of the megnetic field generation.High-energy electrons generated by the relativistic laser pulse are trapped by the quasistatic magnetic field that is sutained by the high-energy electron and bulk electrons in the solid denisty. Using the PIC simulatiuon, we verified the thoretical model. As a result, almost high-energy electrons are trapped by the self-induced magnetic field as the theoretical model shows. Some electron which has more energy than a critical energy, which depends on the insident laser intensity and insident angle, pass through the surface. The electon current generates quasistatic magneteic fields at the inner plasma and rear surface of the target.We proposed the scaling of the hot electron temperature and the electron spectrum of intense laser plasma interaction and verified the scaling using the PIC simulatiuon.