From 1e3b1f6c80f406cfd47662817434108fb3cb67ad Mon Sep 17 00:00:00 2001 From: bmundim Date: Thu, 15 Sep 2011 20:48:00 +0000 Subject: 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 --- doc/documentation.tex | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) 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. -- cgit v1.2.3