As a measure of magnetic field strength in the pdf, I am going to use the magnetic pressure.

Magnetic pressure is an energy density, and in free space in cgs, is given by:

P_B = \frac{B^2}{8 \pi}

In the code, there is a field called 'BE_field' which is the magnetic energy (or pressure) field, given by:

BE\_field = \frac{1}{2} (B_x^2 + B_y^2 + B_z^2)

The B's in the above are in computational units (cu), implying -

BE\_field = \frac{1}{2} (||\vec{B}(cu)||^2) = \frac{1}{2} B^2 (cu)

= \frac{1}{2} \frac{B^2(cgs)}{Bscale^2}

where

Bscale = \sqrt{4\pi *pscale}

Putting this into BE_field gives,

BE\_field = \frac{B^2(8\pi)^{-1}}{pscale} = \frac{P_B}{pscale}

aka - scaled magnetic pressure.