Density fluctuations and polarization features of magnetohydrodynamic waves

In the interstellar medium (ISM), a broad range of turbulent plasmas can be observed by using radio waves. However, only density fluctuations are directly measurable with these radio astronomic tools. If one wants to deduce the underlying features of the turbulence, it is necessary to calculate the relation between density and magnetic fluctuations. Here a magnetohydrodynamic (MHD)-ansatz is taken into account for the ISM turbulence to calculate the fluctuations for the three low-frequency MHD waves.