This version of MAG contains a serial version of Gary Glatzmaier's
rotating spherical convection/magnetoconvection/dynamo code,
modified by Uli Christensen and Peter Olson. 

The code solves the nondimensional Boussinesq equations for
time-dependent thermal convection in a rotating spherical 
shell filled with an electrically conducting fluid. 

The equations of motion are:
the Navier-Stokes equation including Coriolis, Lorentz,Buoyancy,
pressure, viscous, and inertial terms; the heat equation including
advection, diffusion, and uniform-density heat sources; the continuity
equation for velocity and Gauss' law for magnetic field, and the
induction equation for the magnetic field.

All variables are nondimensional; time scale is viscous
diffusion, length scale is shell thickness,temperature scale
is boundary temperature difference, magnetic field and electric
currents use Elsasser number scaling. 

A variety of boundary and initial conditions are selected as options.

Mag uses toroidal-poloidal decomposition for velocity and magnetic
field with  explicit timesteps.Linear terms are evaluated spectrally
(spherical harmonics plus Chebycheff polynomials in radius) and  nonlinear
terms are evaluated on a spherical grid.

Additional technical information is found in:
Olson, P. & Glatzmaier, G.A.,Geophys Astrophys Fluid Dyn 92, 109, 1995;
Phil Trans R Soc Lond A354, 1413, 1996
Olson, P. Christensen, U, Glatzmaier, G.A. J Geophys.Res. 104, 10383, 1999
Christensen, U, Olson, P, Glatzmaier, G.A. Geophys. J. Int 138, 393, 1999
Christensen, et al, Phys Earth Planet Int 128, 25, 2001 (benchmark cases)
(plus more recent papers by the same authors) 


This directory  contains:

1) The set of FORTRAN source code files with suffix ".f".
This includes  sample grid parameter value files with names like
"param32s4.f" for a coarse grid (up to 32 spherical
harmonics, 24 radial grid intervals, and 4-fold symmetry
in phi).

2) A makefile named "makefile".
3) Two documentation files named "MAGDOC" and "VARIABLES".
   The first gives an overview over the components of the code,
   input parameters, structure of output files, etc.
   The second explains the meaning of many of the important 
   variables and arrays used in the code. Both documentation
   files may not be entirely up-to-date!!
4) Sample files with input parameters, par.XXX. The case par.bnch0
   is for rotating convection at an Ekman number of 1E-3,
   starting from a conductive temperature perturbation with
   imposed perturbation with l=4, m=4, and running for a short time.
   This is the "benchmark0" test case in Christensen et al, 2001.
   An other input file is par.bnch1, the dynamo "benchmark1" case
   in Christensen et al.
5) Output files "ls.benchX", "l.benchX", "g.benchx", and "d.benchx"
   obtained with short runs on a Appro (Opteron) workstation
   Explanations of the contents of these files are found
   in MAGDOC.


For test-running the code, do the following steps:

0) Uncompress all files, and create a path (see PATHMAKE)
1) ln -sf param32s4.f param.f  [Link grid parameter file to "param.f"
                                which enters through "include" state-
                                ments into most subroutines].

2) make                        [Compile the program].

3) mv magx magx32s6            [Renaming, optional]

4) magx32s4 <par.bnchX >p.benchX & [Background executin the bench input file]
   (If there is a problem with the par.bnch files, modify the last
    lines, which read:           

     icour=4 
     &end
     &bounds
     &end
        
     (Also, instead of the "&", perhaps a "$" may be required).
        
5) Compare output files

6) REMEMBER TO DELETE, MOVE, or RENAME ALL OUTPUT FILES IN CURRENT
   DIRECTORY BEFORE RE-RUNNING WITH THE SAME "output" FILENAME -- RETAINING
   SAME-NAMED OUTPUT FILES IN THE CURRENT DIRECTORY CAUSES MAG TO CRASH!!