The experimental lower hybrid current drive efficiency at zero electric field is found to agree with theory if the spectrum of the lower hybrid waves is fully accessible to the central region of the plasma. For broad or very low parallel wave number spectra, N∥, for which the plane wave accessibility condition is not fully satisfied, the observed efficiency is higher than predicted. At non-zero electric field, the measurements agree with theories for an electric field dependent efficiency. The model can also be applied to experiments in which a symmetric spectrum of waves is launched, or to cases where the current is driven opposite to the DC electric field if runaway electrons can be neglected. A shift of the deposition zone by superposition of a low N∥ current drive spectrum and a high N∥ symmetric spectrum does not change the current drive efficiency.
低混波电流驱动在零电场下的效率，若低混波谱完全可到达等离子体中心区域，则与理论一致。对于宽谱或极低平行波数N∥，即平面波可到达条件未完全满足的情况，观测到的效率高于理论预测。在非零电场下，测量结果与考虑电场依赖效率的理论相符。该模型也可应用于对称波谱发射的实验，或在可忽略逃逸电子的条件下，电流方向与直流电场相反的情形。通过低N∥电流驱动谱与高N∥对称谱的叠加实现沉积区移动，不会改变电流驱动效率。