FIELD

This card allows fields to be defined over the existing grid.

• SET(s)
• VALUE(s)

The following list itemizes the valid keywords and their meaning.

SET: [string]

defines the name of the quantity to be assigned.

VALUE: [string]

value is an expression to be evaluated across the grid. It can include constants, other solution quantities, and the coordinates X, Y and Z (uppercase).

XRANGE [string]

limits the application of the field statement to range specified. For example, ``[0.3:0.5]'' specifies a closed range from x=0.3 to x=0.5, which includes the endpoints of the range. ``(0.3:0.5)'' specifies an open range from x=0.3 to x=0.5, which excludes the endpoints. Open and closed endpoints can be mixed. A fuzzy comparison is used to make the function more robust.

YRANGE

as XRANGE, but for y-direction.

ZRANGE

as XRANGE, but for y-direction.

STATS [string]

out some statistics for the specified field, such as min, max, average and standard deviation. Typical usage:

field stats=electrons

MATERIAL [string]

MATERIAL keyword limits the application of the FIELD command to the specified material.

SOLVAR [string]

user can request that fluxes be calculated by setting ``set=flux''. The SOLVAR keyword specifies which flux is to be calculated. Typical usage (e.g., for electron currents) is:

field set=flux solvar=electrons type=edge

This command, issued before the solutions is calculated with a ``BIAS'' command, causes the currents to be stored in the field ``fluxelectrons.'' Note that this is an edge field, not a nodal field.

PROFILE3D [string]

3-D field from file name specified. See PROFILE2D for format information.

PROFILE2D [string]

2-D field from file name specified. The 2D and 3D file formats support either uniform spacing or rectilinear spacing. The format is

<nx> <ny> [<nz>]
'u' | 'r'               ;;; uniform or rectilinear spacing
<tensor mesh coordinates>
<ix> <iy> [<iz>] <value at (ix,iy[,iz])>
...

where , , and are the number of grid lines in each dimension (minimum is 2) indicies run from 0 to n-1, inclusive

The indices and value need not be given in any specific order, but the set should be complete.

For a uniform mesh, the <tensor mesh coordinates> consists of a pair of two real numbers representing the bounds for that dimension ( ). Mesh spacing is (U - L) / ( -1).

For a rectilinear mesh, the <tensor mesh coordinates> consists of the two or three lists of real numbers of length (you can have one number per line). These numbers are the locations of mesh lines, and they are assumed to be sorted in increasing order.

The locations of the mesh lines in these files need not correlate to your prophet mesh. Linear interpolation is used to map file values onto the prophet mesh.

For 1d, the values at the endpoints extend to infinity. If you want to truncate assignment outside of the extent, just specify 0 for the value at the start and end of the range.

For 2d and 3d, assignment is truncated outside of the extent specified in the file.

DELETE [string]

the specified field and free its memory.

FILENAME [string]

in 1-D data from file. The format is two reals per line, the first being the x-coordinate, the second being the value.

LIST [logical]

the names and types of all the fields found in the domain.

Examples:
field set=boron value=1e18*exp(-(X-0.1)*(X-0.1)/(2*0.01*0.01))
field set=phosphorus value=1e19*gbox(X,0,0.1,0.01)*gbox(Y,0.5,0.8,0.01)

The function gbox has a constant value in the interval between its second and third arguments, with gaussian fall-off behavior outside that interval with a characteristic length equal to the fourth argument. The first argument is the axis to substitute. This example specifies a flat profile of 1e19 inside the interval (X,Y) = (0-0.1 , 0.5-0.8) with Gaussian decay of characteristic length 0.01 outside.

Less Used FIELD Keywords

TYPE [string]

to specify one of two special field types, either ``edge'' or ``scalar''. An edge field is defined for each of the edges in the structure, e.g., for currents. A scalar field has one value defined for the entire geometry.

CLASS [string]

the class type of this field (default = ``permanent'').

AXIS [string]

reading in 1-D data using the FILENAME command, the AXIS keyword determines whether the data is stored in the x, y, or z direction. The axis is specified by either ``axis=X'', ``axis=Y'', or ``axis=Z''. Default is X.

NEGATE [logical]

reading in 1-D data from a file using FILENAME, multiply the data values by -1. (Not implemented for 2-D or 3-D data).

DISTANCE [string]

each node in the field, find the minimum distance to the interface of the material specified. Typical usage:

       field set=fromOxide distance=oxide

finds minimum distance to the oxide interface for each node.