Friction due to charge exchange with cold neutral atoms in the edge is investigated as a candidate to govern the poloidal rotation in the edge of a tokamak plasma. The Hirshman and Sigmar neoclassical moment approach is used to determine the rotation velocities of the main plasma ions and of one impurity species, when charge exchange friction is included. It is found that the poloidal rotation of the main plasma ions is controlled by charge exchange friction with neutrals. The impurity ion poloidal rotation is governed by the balance between the impurity viscous force and the main-ion-impurity-ion friction force. The results of the calculation are compared with the measurements obtained in the edge of a DIII-D high (H) mode plasma, using charge exchange recombination (CER) spectroscopy. It is found that the measured main ion poloidal rotation can be accurately predicted by the neoclassical theory including the effect of neutrals, assuming a neutral density ⟨nn⟩ = 3 × 1017 m-3 at the separatrix, decreasing exponentially inside the plasma with an e-folding length of 0.012 m, and peaking near the X point region with a poloidal peaking parameter γ ≡ ⟨nn⟩⟨B2⟩/⟨nnB2⟩ = 1.5. However, for the impurity ions, the neoclassical theory including a single impurity charge state, and regardless of the effect of the neutrals, gives a prediction that has the correct sign, but whose value is a factor of 5 or 6 different from the experimental value
周向旋转由托卡马克等离子体边缘的冷中性原子电荷交换引起的摩擦作为候选机制进行研究。采用Hirshman和Sigmar的新经典矩方法，在考虑电荷交换摩擦的情况下，确定主等离子体离子和一种杂质离子的旋转速度。研究发现，主等离子体离子的极向旋转受与中性原子的电荷交换摩擦控制。杂质离子的极向旋转由杂质粘性力与主离子-杂质离子摩擦力之间的平衡决定。计算结果与DIII-D高约束模式等离子体边缘通过电荷交换复合光谱（CER）测量的结果进行了比较。结果表明，在假设分离面处中性密度⟨nn⟩ = 3 × 10^17 m^-3、等离子体内部呈指数衰减且衰减长度为0.012 m、并在X点附近具有极向峰值参数γ ≡ ⟨nn⟩⟨B²⟩/⟨nnB²⟩ = 1.5的条件下，考虑中性原子效应的新经典理论能够准确预测所测得的主离子极向旋转。然而，对于杂质离子，无论是否考虑中性原子效应，仅包含单一杂质电荷态的新经典理论给出的预测虽然符号正确，但其数值与实验值相差5至6倍。