Non linear gyro-kinetic computation of turbulent transport in a fusion device

该项目旨在开发一个软件工具，用于计算嵌入磁场中的完全电离气体中的湍流。这种湍流系统被观察到存在于旨在基于核聚变概念开发未来能源的实验反应堆中。湍流具有负面影响，因为它排出热量和颗粒，降低反应器的效率。因此，了解湍流是如何产生的及其基本特征是非常重要的。在这个项目中开发的数值代码将有助于实现这一目标。随着对湍流输运的更好理解，有可能预测反应堆概念的特性，而无需实际建造它。虽然目前还不清楚，但可能以减少与湍流状态相关的负面影响的方式优化设计。该项目的出发点是一个现有的线性稳定性代码，与它可以确定，如果等离子体是不稳定的小尺度不稳定性。这种线性方法不允许确定这种初始不稳定性一旦其幅度增长到显著水平将如何及时发展。对于后一种情况，需要增加描述不同不稳定模式之间相互作用的项。项目的目标是添加这些交互术语。在相互作用项被添加之后，人们面临着计算上的需求问题。由于计算机在时间和内存方面的限制，这些计算只能在联合收割机上进行。

This project aims at developing a software tool for the calculation of turbulence in a fully ionised gas embedded in a magnetic field. Such a turbulent system is observed to exist in the experimental reactors that aim at developing a future energy source based on the concept of nuclear fusion. The turbulence has a negative influence since it expels heat and particles reducing the efficiency of a reactor. It is,therefore, of importance to understand how the turbulence is generated and what its basic characteristics are. The numerical code developed in this project will help to achieve this goal.With a better understanding of the turbulent transport it is possible to predict the properties of a reactor concept without actually having to build it. Although it is unclear at present, it might be possible to optimise the design in a way that reduces the negative effects associated with the turbulent state. The starting point of the project is an existing linear stability code, with which one can determine if the plasma is unstable against small scale instabilities. Such a linear approach does not allow to determine how this initial instability will develop in time once its amplitude has grown to a significant level. For the latter case one needs to add the terms that describe the interaction between the different unstable modes. Goal of the project is to add these interaction terms. After the interaction terms have been added one faces a computationally demanding problem. Because of computer limitations, both in time as well as in memory, these computations can only be made on computers that combine many CPUs.