Magnetic reconnection in 3D fusion devices is investigated. With the use of Boozer co-ordinates, we reduce the non-linear resistive magnetohydrodynamic equations in the limit of large aspect ratio and finite pressure fluctuations, to obtain a set of non-linear equations suitable for magnetic reconnection studies in stellarators. Magnetic flux unfreezing due to a finite electron mass is also considered. Equations that govern the linear regime and some of their general properties are given. We emphasise the role of magnetic geometry and identify how some aspects of stellarator optimisation could have an impact on reconnecting instabilities, in particular by exacerbating those enabled by electron inertia. The effect of 3D coupling on the linear reconnection rates and the mode structure is quantitatively addressed in the case in which the equilibrium rotational transform has one specific resonant location for which one mode can reconnect while coupled to an arbitrary number of non-resonant harmonics. The full problem is rigorously reduced to an equivalent cylindrical one, by introducing some geometrically modified plasma inertial and dissipative scales. The 3D scalings for the growth rates of reconnection instabilities and their destabilisation criteria are given.

研究了3D融合设备中的磁重新连接。通过使用Boozer坐标，我们在大长宽比和有限压力波动的范围内简化了非线性电阻性磁流体动力学方程，从而获得了一组适用于恒星器中磁重联研究的非线性方程。还考虑了由于有限的电子质量而引起的磁通解冻。给出了控制线性状态及其某些一般性质的方程。我们强调了磁性几何学的作用，并确定了恒星优化的某些方面如何对重新连接的不稳定性产生影响，特别是通过加剧电子惯性所引起的不稳定性。在平衡旋转变换具有一个特定的共振位置的情况下，定量地解决了3D耦合对线性重新连接速率和模式结构的影响，一种模式可以在耦合到任意数量的非共振谐波时重新连接一个特定的共振位置。通过引入一些几何修饰的等离子体惯性和耗散尺度，将整个问题严格地减小到等效的圆柱体。给出了重新连接不稳定性的增长率的3D缩放比例及其不稳定标准。通过引入一些几何修饰的等离子体惯性和耗散标度。给出了重新连接不稳定性的增长率的3D缩放比例及其不稳定标准。通过引入一些几何修饰的等离子体惯性和耗散标度。给出了重新连接不稳定性的增长率的3D缩放比例及其不稳定标准。