含磁性离子的自旋极化电子等离子体的超快动力学
Ultrafast dynamics of a spin-polarized electron plasma with magnetic ions
AI总结：
本研究构建了描述自旋极化电子气与磁性离子相互作用的VPLL平均场模型，开展线性响应分析确定自旋模式稳定性条件，并开发高精度几何哈密顿数值代码，研究温稠密物质参数下的电荷与自旋不稳定性相互作用。
摘要：
我们构建了一个平均场模型，用于描述自旋极化电子气与固定的、带正电且磁矩随时间演化的离子相互作用的非线性动力学。可动电子由二维相空间$(x,v)$中的四分量分布函数建模，服从Vlasov-Poisson方程组。离子的自旋密度由Landau-Lifshitz方程建模，该方程包含离子-离子与电子-离子的磁交换项。我们针对Maxwell-Boltzmann平衡情形，对耦合的Vlasov-Poisson-Landau-Lifshitz（VPLL）方程开展了线性响应研究，重点关注自旋色散关系。我们确定了自旋模式的稳定或不稳定条件，这些条件本质上取决于电子自旋极化率$η$和电子-离子磁耦合常数$K$。我们还基于N. Crouseilles等人2023年发表于《Journal of Plasma Physics》第89卷第2期905890215页的几何哈密顿方法，开发了一套基于欧拉网格的全非线性VPLL方程计算代码。该技术能让我们在守恒量（如离子自旋矢量的模和总能量）上实现极高的精度。线性区域的数值测试结果与线性响应理论的估算一致。对于双流平衡情形，我们研究了电荷区与自旋区中出现的不稳定性之间的相互作用。模拟中使用的参数集（密度接近固体密度，约$10^{29} \rm m^{-3}$，温度约为10 eV）可能与某些惯性聚变实验中出现的温稠密物质区域相关。
英文摘要：
We construct a mean-field model that describes the nonlinear dynamics of a spin-polarized electron gas interacting with fixed, positively-charged ions possessing a magnetic moment that evolves in time. The mobile electrons are modeled by a four-component distribution function in the two-dimensional phase space $(x,v)$, obeying a Vlasov-Poisson set of equations. The ions are modeled by a Landau-Lifshitz equation for their spin density, which contains ion-ion and electron-ion magnetic exchange terms. We perform a linear response study of the coupled Vlasov-Poisson-Landau-Lifshitz (VPLL) equations for the case of a Maxwell-Boltzmann equilibrium, focussing in particular on the spin dispersion relation. Condition of stability or instability for the spin modes are identified, which depend essentially on the electron spin polarization rate $η$ and the electron-ion magnetic coupling constant $K$. We also develop an Eulerian grid-based computational code for the fully nonlinear VPLL equations, based on the geometric Hamiltonian method first developed in [N. Crouseilles et al. Journal of Plasma Physics, 89(2):905890215, 2023]. This technique allows us to achieve great accuracy for the conserved quantities, such as the modulus of the ion spin vector and the total energy. Numerical tests in the linear regime are in accordance with the estimations of the linear response theory. For two-stream equilibria, we study the interplay of instabilities occurring in both the charge and the spin sectors. The set of parameters used in the simulations, with densities close to those of solids ($\approx 10^{29} \rm m^{-3}$) and temperatures of the order of 10 eV, may be relevant to the warm dense matter regime appearing in some inertial fusion experiments.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
