[FLASH-BUGS] is the proton mass right in flash?

[Leonid Malyshkin]

Hello,

I have the following two questions about flash.

FIRST question. I use flash for MHD:
	#Modules file for rosetta generated by setup -auto
	INCLUDE database/amr/paramesh2.0
	INCLUDE driver/time_dep
	INCLUDE hydro/mhd/divb_diffuse
	INCLUDE io/amr/hdf5_serial
	INCLUDE materials/eos/gamma
	INCLUDE materials/magnetic_resistivity/const
	INCLUDE materials/viscosity/constant
	INCLUDE mesh/amr/paramesh2.0/second_order_old
	INCLUDE util/tools
	INCLUDE util/wrapping

My hydro initial conditions are ideal gas with pressure, density, 
and gamma index all constant in space. I check the initial conditions 
with the initial .chk point file, rosetta_hdf5_chk_0000, and find the 
following:
	density rho = 1.00000 g/cm^3 
	pressure P = 6.00000e-4 erg/cm^3 
	temperature T = 7.21630e-12 K 
	specific internal energy eint = 9.00000e-4 erg/g
	gamma index gamma = 5/3

Next, I check equation of state for my ideal gas:
	P = rho*k_B*T/(rho/n) = rho*k_B*T/m, 
where k_B is the Boltzmann constant, n is concentration (particles 
per cm^3), and by definition
	m = rho/n 
is the averaged pass of the particles of the ideal gas.
Using data for P, rho and T, one finds
	m = rho*k_B*T/P = 1.00000*1.38062e-16*7.21630e-12/6.00000e-4
	m = 1.66049e-24 gramm

This is a very very strange result, because 
	the proton mass is 1.67261e-24 gramm, it's larger by 1% !!!
	the average of proton and electron masses (assuming fully 
           ionized proton plasma) is 0.5*(m_p+m_e)=0.83676e-24 gramm 

Does flash have the proton mass and Boltzmann constant right?

--------------------------------------------------------

SECOND question.

In the flash guide, page 92, section 9.1.3.1, "Thermal diffusion", one 
can read in the line just before the line previous to equation (9.13)
that the thermal diffusivity is \lambda = \sigma/(\rho*c_p), where
\sigma is the thermal conductivity, and \rho is density. This looks 
extremely misleading, because c_p is not defined there, and one naturally 
assumes that c_p is the specific heat capacity at constant pressure. I 
believe this may be wrong because is may should have been c_v, which is 
the specific heat capacity at constant volume. Note that c_p/c_v=gamma. 
The reason i ask this question is not that i want to point out a minor 
misprint in the guide, but because I may be wrong and c_p may be the  
right heat capacity to use, in case the heat conduction equations in 
flash are written in some unconventional way. So, what should really be 
there, c_p or c_v?

Thank you very much,
Leonid