calculate magnetic field intensity for a given baryon overdensity at a given redshift

Qin Han
  • 16 Mar '22


I am trying to get the magnetic field intensity versus baryon overdensity at a certain redshift. The information I need is the same as in the Fig 3 of this paper Marinacci et al. (2018) (; the only difference is that I need it for a redshift range of 0-3.0.

Using the names in 'PartType0 (gas)', I think that I need to calculate it using 'MagneticField' of the 'Full Snaps', but I don't know how to do it exactly. For example, for 'TNG300-1', z=0, how do I find the 'MagneticField' information and what would the expression for magnetic field intensity look like?

Many thanks,

Dylan Nelson
  • 17 Mar '22

Hi Qin,

Magnetic field is a 3-vector field (like Velocities). Assuming you had a very large amount of memory, you could simply load it like this:

b = il.snapshot.loadSubset(path,snap,'gas','MagneticField')
bmag = np.sqrt(b[:,0]**2 + b[:,1]**2 + b[:,2]**2)

note the units are not yet Gauss, you would be careful to convert the units.

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