Development of Vlasov code based on multi-moment scheme and its application to multi-scale turbulence

提出了一种新的数值格式——多矩格式。我们将其应用于等离子体动力学模拟，并证明了该方案能够保持高精度的精细尺度结构。基于MM格式，我们还研究了磁化约束聚变等离子体中的多尺度相互作用。我们发现小的磁岛对离子温度梯度（ITG）驱动的不稳定性有稳定作用，而大岛引起的有理面分离则会破坏ITG模式的不稳定性。

New numerical scheme named as the Multi-Moment (MM) scheme is proposed. We have applied it to plasma kinetic simulation and demonstrated that the MM scheme is capable of keeping fine scale structure in high accuracy. Based on the MM scheme, we have also investigated the multi-scale interaction in magnetized confined fusion plasmas. We found that the small magnetic island has a stabilizing effect on the ion temperature gradient (ITG) driven instability, whereas the separation of the rational surfaces caused by the large island destabilizes the ITG mode.