论文标题
引力束 - 血压不稳定性的线性分析
Linear analysis of the gravitational beam-plasma instability
论文作者
论文摘要
当快速的粒子与Horndeski重力理论的大量标量模式相互作用时，我们研究了重力部门中梁血压不稳定性的众所周知现象，从而导致后一个振幅的线性生长。按照标准电磁案例中使用的方法，我们从引力等离子体的介电表示开始，如先前对标量Horndeski模式的Landau阻尼的分析中所介绍的那样。然后，我们建立了修改的Vlasov-Einstein方程，首先使用Dirac Delta函数来描述快速光束分布。这样，我们提供了分散关系的分析表达，并证明了Horndeski标量模式的线性演化的非零生长速率的存在。然后，使用梯形束分布函数进行数值研究，该功能确认了分析结果，并允许证明随着束扩散的增加，生长速率如何降低。
We investigate the well-known phenomenon of the beam-plasma instability in the gravitational sector, when a fast population of particles interacts with the massive scalar mode of an Horndeski theory of gravity, resulting into the linear growth of the latter amplitude. Following the approach used in the standard electromagnetic case, we start from the dielectric representation of the gravitational plasma, as introduced in a previous analysis of the Landau damping for the scalar Horndeski mode. Then, we set up the modified Vlasov-Einstein equation, using at first a Dirac delta function to describe the fast beam distribution. This way, we provide an analytical expression for the dispersion relation and we demonstrate the existence of non-zero growth rate for the linear evolution of the Horndeski scalar mode. A numerical investigation is then performed with a trapezoidal beam distribution function, which confirms the analytical results and allows to demonstrate how the growth rate decreases as the beam spread increases.
