Add a few lines about units adopted, in particular the conversion factors

for your convenience. Please review these numbers though.


git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinBase/HydroBase/trunk@41 57fe0bb3-ccba-405f-9b23-de0201f165b7

1 files changed, 15 insertions, 1 deletions

diff --git a/doc/documentation.tex b/doc/documentation.tex
index 0b87fc0..91d5272 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -132,7 +132,7 @@ to couple to a spacetime solver and which are usually needed by analysis thorns.
 a common set of variables by different hydrodynamics codes creates the possibility to share
 parts of the code, e.g.\ initial data solvers or analysis routines. 
 
-Currently the defined primitive variables are (see~\cite{livrevgrfd} for
+Currently the defined primitive variables are (see~\cite{livrevgrrfd} for
 details):
 \begin{itemize}
  \item \verb|rho|: rest mass density $\varrho$
@@ -185,6 +185,8 @@ conventions
   M_\mathrm{sun} = 1 &;& c = G = 1
 \end{eqnarray}
 which are commonly used in astrophysics and in relativity.
+The former sets the mass scale to the solar one and the latter
+adopts the same units for time, length and mass.
 
 We assume the following definitions and constants of nature:
 \begin{eqnarray}
@@ -211,6 +213,18 @@ magnetic field:
   [B] & = & 1/[L]\; / \sqrt{\epsilon_0 G / c^2}
 \end{eqnarray}
 
+Inserting the SI units into the above unit correspondences, 
+we find the following conversion factors:
+\begin{equation}
+ M_\mathrm{sun} \equiv 1.477\, \mathrm{km} 
+                \equiv 4.92673\, \mathrm{\mu s} 
+                \equiv 8.344956\cdot 10^{15}\, \mathrm{T},
+\end{equation}
+where T (Tesla) is the magnetic field unit in SI, 
+$1\,\mathrm{T}=1\,\mathrm{N/(A\cdot m)}$, or in its cgs equivalent,
+$1\,\mathrm{Tesla} = 10^4\,\mathrm{Gauss}$. 
+
+
 \section{Acknowledgments}
 
 This thorn was produced by Tanja Bode, Roland Haas, Frank L\"offler, and Erik Schnetter.