We perform a study of system-scale to gyro-radius scale electromagnetic modes in a pedestal-like equilibrium using a gyrokinetic code ORB5, along with a comparison to the results of wimulations in a local gyrokinetic code, GS2, and an MHD energy principle code, MISHKA. In the relevant large-system, short wavelength regime, good agreement between the gyrokinetic codes is found. For global-scale modes, reasonable agreement between MHD and the global gyrokinetic code is observed. There are various formulational and implementational issues with using standard gyrokinetic codes in this limit, so even this level of agreement is promising. In order to correctly model the physics it is important to keep the effect of magnetic field strength fluctuations (which are not directly included in ORB5) in this case, where the gradient of β is large. The pressure stability threshold does not change substantially between the MHD and global gyrokinetic simulations, for the conditions presen...

中文翻译：

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将全局陀螺动力学模拟中的电磁不稳定性与局部模型和MHD模型进行比较

我们使用陀螺动力学代码ORB5在类似基座的平衡状态下对系统规模到陀螺半径尺度的电磁模式进行了研究，并与局部陀螺动力学代码GS2和MHD能量原理代码的仿真结果进行了比较，MISHKA。在相关的大系统，短波长范围内，可以找到陀螺动力学代码之间的良好一致性。对于全局模式，可以观察到MHD和全局陀螺代码之间的合理一致性。在此限制下使用标准陀螺动力学代码存在各种制定和实施方面的问题，因此即使达到这一水平的协议也很有希望。为了正确地建立物理模型，在这种情况下（β的梯度很大），保持磁场强度波动（不直接包含在ORB5中）的影响很重要。