Turbulent Velocity (vturbi)

This parameter allows extra line broadening to be introduced into the calculation of the synthetic spectrum. The value is in km s$^{-1}$. This quantity enters into the calculation of the line profile function, which is used by the line opacity and emissivity. The line profile function is a Voigt profile, which resembles a Gaussian in the Doppler core. The turbulent velocity then enters into the `sigma' of the Gaussian. The Gaussian 'sigma' in velocity units is $(v_{turb}^2+v_{therm}^2)^{1/2}$ where $v_{therm}$ is the ion thermal speed.