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为了理解超强激光与等离子体相互作用中产生的自生磁场形成机制和电子热传导特性,采用相对论电磁粒子模拟程序,估算了不同激光功率密度下,在等离子体表面所形成的电磁不稳定性产生的自生磁场大小和空间分布,得到了超热电子和经典Spitzer-Harm理论描述的电子热流随激光功率密度的演化情形。结果表明,非Maxwell速度分布的等离子体,由于电子初始时刻的无规则热运动,在等离子体上激发电磁不稳定性,而不稳定性激发的强电磁场使电子束在非常短的距离内沉积能量,同时对在激光有质动力推开电子时形成的超热电子能量输运产生抑制作用。这一研究结果对更好理解惯性约束核聚变“快点火”过程中自生磁场的产生、电子热传导等方面有帮助的。
In order to understand the formation mechanism of self-generated magnetic field and electronic thermal conductivity in the interaction between super-laser and plasma, the relativistic electromagnetic particle simulation program was used to estimate the electromagnetic instabilities generated on the plasma surface under different laser power densities The evolution of the electron heat flux as a function of the laser power density is derived from the size and spatial distribution of the self-generated magnetic field and the superheated electron and the classical Spitzer-Harm theory. The results show that plasma with non-Maxwell velocity distribution excites electromagnetic instability on the plasma due to the random thermal motion at the initial moment of the electron, while the strong electromagnetic field induced by instability causes the electron beam to deposit energy in a very short distance , While inhibiting the transport of hot electron energy formed when the laser has a motive force pushing electrons away. The results of this study are helpful to better understand the generation of spontaneous magnetic field and electronic thermal conduction in the process of inertial confinement fusion and fast ignition.