Dear Editor,

here is my report on the manuscript "Magnetic Prandtl number dependence of 
turbulence generated by the chiral MHD dynamos" by J. Schober, etal.

The authors investigate the influence of the value of the magnetic Prandtl number 
on the properties of the turbulent MHD in plasma generated by chiral MHD dynamos
based on the assumtion of the existence of an asymmetry in the number density 
of left- and right-handed fermions. Strictly speaking, the existence of turbulent MHD dynamos, i.e.,
the generation of a uniform macroscopic magnetic field, are usually related 
to the turbulent motion of electrically conductive environments. However, the magnetic
fields can be significantly amplified in chiral MHD dynamos and, through the Lorentz term 
in the MHD equations, can nontrivialy drive turbulence as well as turbulent processes. 
In the manuscript, the properties of chiral magnetically driven turbulence is 
investigated using numerical simulations and, as it was already mentioned, the main aim
of the manuscript is to analyze the influence of the value of the turbulent Prandtl number
on these properties.

First of all, a brief theoretical description of the problem is given and three typical phases of 
time evolution of the chiral magnetically driven turbulence are described. The authors then 
solve the problem using numerical simulations with the so-called PENCIL CODE in three dimensions
with periodic conditions using various resolutions. New results in the manuscript are related
to the inclusion of various values of the magnetic Prandtl number (0.5<Pr_M<10). Generated
turbulent state of the system is characterized by the ratio of the kinetic energy to
the magnetic energy and this ratio is investigated as a funcion of time and various 
other characteristics especially of the magnetic Prandtl number. It is shown that, for
given values of the parameters, the ratio of the kinetic energy to the magnetic energy
stays almost constant but it decreases significantly with increasing of the value
of the magnetic Prandtl number. The same is true as for the obtained maximal Reynolds number
of the turbulent system.

The manuscript is well written. The language is clear and comprehensible. The results are
scientifically sound and I consider them as important.  Therefore, I can recommend the
manuscript to be published in Geophysical and Astrophysical Fluid Dynamics.

I have only one recommendation. Because the value of the magnetic Prandtl number plays
the central role in the present study, I think that it would be instructive to mention in the
manuscript (at an appropriate place) the existence of recent nontrivial theoretical calculations
of the turbulent magnetic Prandtl number in turbulent MHD systems with and without 
vilation of spatial parity (PHYSICAL REVIEW E 84, 046311 (2011) and 
PHYSICAL REVIEW E 87, 043010 (2013)), where it was shown that 1) it seems that the 
magnetic Prandtl number is stable perturbatively and 2) that the presence of spatial 
parity violation decreases its value. Note that theoretical prediction for the 
turbulent magnetic magnetic Prandtl number is approximatelly 0.71 and is perfectly in the 
interval of magnetic Prandtl numbers used in the manuscript.  

Sincerely yours