论文标题
在无碰撞平板等离子体中的小型撕裂模式的物理学
The physics of a small-scale tearing mode in collisionless slab plasmas
论文作者
论文摘要
微并且已被广泛报道为撕裂的均等电子温度梯度驱动的等离子体不稳定性，这导致磁通表面的细小撕裂，从而导致磁场线的重新连接和磁岛的形成。在平板几何形状中，以前已经证明了驱动机构需要有限的碰撞频率。但是，我们在线性陀螺仪模拟中发现，即使在低和零碰撞频率下，无碰撞的细撕裂平价不稳定也存在。详细的研究表明，这些平板模式也是由电子温度梯度驱动的，但对电子有限的拉莫尔半径效应敏感，并且径向波数比双重波数小得多，这与离子Larmor半径相当。此外，即使在静电极限和电磁效应中，它们也存在于这种无碰撞撕裂模式的稳定影响。一个分析模型表明，这种无碰撞的小规模撕裂模式与撕裂的平均板电子温度梯度（ETG）模式一致，该模式比经常研究的扭曲奇偶校验ETG模式更不稳定。这种小规模的撕裂奇偶校验模式可以导致磁岛，这反过来会影响磁化等离子体中的湍流传输。
Microtearing modes have been widely reported as a tearing parity electron temperature gradient driven plasma instability, which leads to fine scale tearing of the magnetic flux surfaces thereby resulting in reconnection of magnetic field lines and formation of magnetic islands. In slab geometry it has previously been shown that the drive mechanism requires a finite collision frequency. However, we find in linear gyrokinetic simulations that a collisionless fine-scale tearing parity instability exists even at low and zero collision frequency. Detailed studies reveal that these slab modes are also driven by electron temperature gradient but are sensitive to electron finite Larmor radius effects, and have a radial wavenumber much smaller than the binormal wavenumber, which is comparable to the ion Larmor radius. Furthermore, they exist even in the electrostatic limit and electromagnetic effects actually have a stabilising influence on this collisionless tearing mode. An analytic model shows that this collisionless small scale tearing mode is consistent with a tearing parity slab electron temperature gradient (ETG) mode, which can be more unstable than the twisting parity ETG mode that is often studied. This small-scale tearing parity mode can lead to magnetic islands, which, in turn, can influence turbulent transport in magnetised plasmas.
