... Previous: Determination of the 'diffusion . Fluctuating moment (see eq.(1)) can be estimated as: . So for D we can write the equation which differs from eq.( ... where -turbulent velocity, -characteristic scale of the turbulence. ... The turbulent velocity is less or equal to the sound speed, (in opposite case a great bulk of energy will dissipate in the form of shock waves), that's why we can write: . ... So we can evaluate v (in this case it is the stellar wind velocity, ): . ...