Diffusion in plasma is considered with the help of the moment equations. If low-frequency waves are present which move the ions, diffusion can arise due to non-linearly saturated waves which cause an energy transfer from electrons to ions, or also due to growing waves. Already in weak turbulence the order may exceed the classical diffusion, e.g. for resistive drift waves.In slab geometry the diffusion (or the anomalous resistance) depends in the case of electrostatic waves on the Coulomb force ni E⊥, ni being the ion perturbation and E⊥ the electric field of the waves perpendicular to the density gradient and to the magnetic field. In an axisymmetric torus the diffusion is changed essentially by a factor (1+⋅/⋅⊥), since electric fields parallel to the magnetic field contribute.
プラズマ中の拡散は，モーメント方程式を用いて考察される．イオンを動かす低周波波動が存在する場合，電子からイオンへのエネルギー輸送を引き起こす非線形飽和波動や，成長する波動によって拡散が生じ得る．弱い乱流ですでに，例えば抵抗性ドリフト波の場合，その大きさは古典拡散を超え得る．スラブ幾何学において，拡散（または異常抵抗）は，静電波の場合，クーロン力ni E⊥に依存する．ここで，niはイオン摂動，E⊥は密度勾配および磁場に垂直な波動の電場である．軸対称トーラスでは，磁場に平行な電場が寄与するため，拡散は本質的に(1+⋅/⋅⊥)の因子だけ変化する．