Error field source identification in early ITER plasmas

Above a critical threshold, error fields in toroidal magnetic confinement schemes can be disastrous for maintaining a high energy density fusion plasma. These 3D fields break toroidal symmetry, cause a loss of confinement, and may spawn instabilities leading to disruption. Their possible origin and optimal correction is a topic of pertinent interest for study in planning the operation of future fusion experiments. We conduct a study on linear error field source modeling using GPEC to analyze the n=1 sources from the tilting and shifting of poloidal-field and other coils, and calculate the ideal correction current in the ITER midplane error field correction coils. We consider multiple different early operational scenarios that will be relevant to early campaigns in ITER. We present results in the form of error fields from each scenario and their dominant mode overlaps, as well as the ideal current and phase in the correction coils. Such research is necessary to gain an understanding of how the error fields will behave at higher currents, where it is too risky to measure directly via compass scans due to the increased risk of damage due to disruption.