Some physical quantities for paper

Magnetic field strength

To get the magnetic field strength of the flows for the paper in gauss, I think I can do this,

Take the computational magnetic pressure and multiply by pscale to get magnetic pressure in cgs,

B(cgs)2/8pi = (B(cu)2/2)*pscale

Then multiply by 8pi and take the square-root to get B (cgs).

Now, I am pretty sure that the unit of gauss describes 'B', but wikipedia says the unit is for the flux density, which I suppose one might interpret as energy density aka magnetic pressure. If that were the case, one would not take the square root..

Considering just B, I get,

B = 1.3 microgauss

This seems reasonable, considering typical estimates for molecular clouds and ISM are ~ 10 microgauss..

Ram pressure

In my physics.data, xmu = 1.27, which seems to be the mean molecular weight in the code. Mean molecular weight is the mean mass of a particle in atomic mass units, or amu. One amu is technically 1/12 the mass of Carbon-12, and so is approximately the mass of 1 nucleon, or equivalently, one proton (m_H).

rho = n * xmu * amu

Xmu seems to be used to set the scales for velscale (which is a scaled sound speed). It seems then that this means the particles in the gas are effectively *mostly* hydrogen with a small fraction (25%?) being 2x the mass of hydrogen, ie Helium.

Pram = n*amu*xmu*v2

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