Active subspace analysis is a useful computational tool to identify and exploit the most important linear combinations in the space of a model’s input parameters. These directions depend inherently on a quantity of interest, which can be represented as a function from input parameters to model outputs. As the dynamics of many plasma models are driven by potentially uncertain parameter values, the utilization of active subspaces to perform global sensitivity analysis represents an important step in understanding how certain physical phenomena depend upon fluctuations in the values of these parameters. In the current paper, we construct and implement new computational methods to quantify the induced uncertainty within the growth rate generated by perturbations in a collisionless plasma modeled by the one-dimensional Vlasov–Poisson system near an unstable, spatially-homogeneous steady state in the linear regime.

中文翻译：

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通过活动子空间对等离子体不稳定性进行全局敏感性分析

主动子空间分析是一种有用的计算工具，可识别和利用模型输入参数空间中最重要的线性组合。这些方向本质上取决于感兴趣的数量，该数量可以表示为从输入参数到模型输出的函数。由于许多等离子体模型的动力学是由潜在不确定的参数值驱动的，因此利用活动子空间进行全局敏感性分析代表了理解某些物理现象如何依赖于这些参数值的波动的重要一步。在本文中，我们构建并实现了新的计算方法，以量化由接近不稳定、空间均匀稳定状态的一维 Vlasov-Poisson 系统建模的无碰撞等离子体中的扰动产生的增长率内的诱导不确定性。政权。