The effect of a non-uniform effective ion charge distribution on the dynamo contribution to the plasma resisitivity of a reversed field pinch is studied, based on a stationary energy or helicity balance. The radial distribution of the impurity is obtained from the ETA-BETA II line emission profiles. It is found that the main impurity ions are concentrated in the outer region of the plasma and, consequently, the effective ion charge, Zeff, is close to one everywhere, except in a small slab close to the plasma border, where it can be as high as three to four. The loop voltage required to sustain the RFP configuration with such 'hollow' Zeff profiles has to balance a higher dissipation in the outer region; hence, the apparent resistivity on axis is considerably greater than in the case of uniform Zeff. This effect could also be present in other RFP devices and might very well bridge the gap that was observed previously between the average effective ion charge and the resistivity anomaly factor, particularly for the low plasma density operation.
非均匀有效离子电荷分布对反场箍缩等离子体电阻率中发电机贡献的影响，基于稳态能量或螺旋度平衡进行了研究。杂质径向分布由ETA-BETA II线发射剖面获得。研究发现，主要杂质离子集中在等离子体外部区域，因此有效离子电荷Zeff在除靠近等离子体边界的一个小薄层外处处接近1，而在该薄层内Zeff可高达3至4。维持具有这种“中空”Zeff分布的反场箍缩位形所需的环向电压必须平衡外部区域较高的耗散；因此，在均匀Zeff情形下，视在电阻率在轴心处显著更大。这一效应也可能存在于其他反场箍缩装置中，并且很可能弥合了先前观察到的平均有效离子电荷与电阻率反常因子之间的差距，尤其是在低等离子体密度运行条件下。