README.txt written by E. Pariat on Dec 15th

This folder contains several magnetic field data set necessary for the
direct volume computation of the helicity of James Leake "stable" simulation. "stable" data comes from simulation case SD (Strong Dipole) in Leake, Linton and Antiochos (2013).

Each files correspond to a particular instant.
The files are labeled "t@" with @ corresponding to 2t0 from the start of the run (t0 being the time scale).

The ".sav" files correspond to  IDL save file format. 
They can be restored with e.g.:
IDL> restore,'stable_t150_unigrid.sav'

The data are in non-dimensional units. A scaling is provided in Leake, Linton and Antiochos (2014) though it is not necessary for the project. The computation shall be done in non-dimensional units. 

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The "unigrid" cases correspond to a uniformly spaced grid. 
The number of points of the domain is: Nx =     233  ; Ny =     233  ; Nz =     174
The uniform mesh size is: DDG =      0.85908951

The limits of the interpolated grid is (in units of L0, the length scale)
Xmin =      -99.654383  ; Xmax =       99.654383
Ymin =      -99.654383  ; Ymax =       99.654383
Zmin =      0.36184211  ; Zmax =       148.98433

Compared to the original data of Leake et al 13, the bottom boundary
correspond to the photospheric level, the top boundary to z=150 L0 and
the side boundary have been trimmed. 

The magnetic field and velocity fields have been interpolated on this grid. 


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Each dataset, contains the following variables:

Instant= value of the corresponding instant of each data set,  given
in units of t0 (the time scale). The name of the file is twice the
value instant.

xngrid,  yngrid & zngrid  = 1D arrays corresponding to "x" , "y" and
"z" values of the mesh points along the three axes of the domain. They are uniformly spaced. 

buni = 4D array containing the vector components of the magnetic
field at the given instant. The data are in units of B0 (the magnetic field scale). The two first dimensions of the array correspond to the horizontal directions (hence to 'xngrid' and 'yngrid'). The third dimension of the array correspond to the vertical direction (hence to 'zngrid'). The fourth dimention correspond to the three component of the field: 0='Bx' ; 1='By' & 2='Bz'.


===
put 
One obtains for example:

IDL> restore,'stable_t300_unigrid.sav'
IDL> help
% At $MAIN$          
BUNI            DOUBLE    = Array[233, 233, 174, 3]
INSTANT         DOUBLE    =        150.00028
XNGRID          DOUBLE    = Array[233]
YNGRID          DOUBLE    = Array[233]
ZNGRID          DOUBLE    = Array[174]