Field

Field Parameters

kind (string, default = regular)

Type of field algorithm; one of:

• regular

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

  Sets its guard cells values by communication or boundary conditions.

• interior

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

  Field whose guard cells are expected to be invalid; when the field is shifted in a moving window simulation, (newly) interior cells in a domain are filled from the (formerly) interior cells on other domains.

• depField

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

  Field that fills guard cells and interior cells (during messaging) by adding together the values for a cell on all domains that have that cell (either as interior or a guard cell). Particles are written into depFields.

• funcField

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

  Field that fills guard cells, or newly interior cells in a moving window simulation, by calculating their values from a function.

Each of these kinds is explained in detail in the following sections. If no kind is given, the default (and usually correct choice for most simulations) will be used by Vorpal.

numComponents (integer, default = 1)

Number of field components. Other field component values include:

• 1: scalar field
• 3: vector field
• 4: edge4v vector
• 9: tensor field

offset (string)

Offset positions where the field values are located within a cell. offset values include:

• none

  Corner with lowest coordinates.

• center

  Center of cell.

• edge

  Component j is at the center of the lowest edge parallel to the jth direction.

• face

  Component j is at the center of the lowest face perpendicular to the jth direction.

• edge4v

  For rhoJ, 0-component is at node, 1 is at x-center-edge, 2 at y-center-edge, 3 at z-center-edge

overlap (integer vector)

depField default = [1 2], default for all others = [1 1] Number of lower and upper guard cells. The guard cells are important if higher order particles are near the simulation boundaries or for communications when running in parallel.

dumpPeriodicity (integer, default = Multifield dumpPeriod setting)

How often to dump the Field data relative to that set by the global variable globalvariables.dumpPeriodicity. For example, if a simulation generates 10 dumps, then setting the Field’s dumpPeriodicity to 3 will dump the Field data on the 3rd, 6th, and 9th dumps. Setting dumpPeriodicity = 0 will suppress dumping. If dumpPeriodicity is omitted from the attribute set, Field will inherit its parent MultiField’s dumpPeriodicity setting. If Field and its parent MultiField have different values of dumpPeriodicity, Field will only dump when both its own dumpPeriodicity and its parent MultiField’s dumpPeriodicity coincide, that is, it will not dump at a time when there is no MultiField dump.

For more dumping options, see the Dumping Fields, Particles, and GridBoundaries section in the VSim User Guide.

interpolation (string)

No offset default = linearFromNodalFields, default for all others = esirk1stOrder. Defines the interpolation method used for particles. Values include:

• linearFromNodalFields

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

• polynomial

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

• esirkHalfSine

  Works with VSimPD and VSimPA licenses.

• esirkGaussian

  Works with VSimPD and VSimPA licenses.

• esirk1stOrder

  Works with VSimBase, VSimEM, VSimPD, VSimPA, and VSimMD licenses.

• esirk2ndOrder, … esirk7thOrder

  Works VSimPD and VSimPA licenses.

No offset default = linearFromNodalFields, default for all others = esirk1stOrder

The default for offset = none is linearFromNodalFields, otherwise the default is esirk1stOrder. When using higher order particles, maxIntDepHalfWidth must be set accordingly in the Grid block (see Additional Attributes for Particle Simulations).

dumpOnly (integer)

If set to true 1 in a Field block of kind = depField then depositors depositing into that field will only execute at dump time. This is useful for occurrences of depField that are dumped but not needed for the update, such as charge density for EM PIC.

skipChecks (integer, default = 0)

When restoring a simulation with static fields or other fields that do not dump regularly, Vorpal performs an automated check on the local dumpSteps line or Expression block to ensure that restoring from an older .h5 dump will not adversely impact the simulation. The user can set this attribute to 1 to signal that the field is safe to restore from any dump step and thus ignore these checks.

For more dumping options, see the Dumping Fields, Particles, and GridBoundaries section in Output Data in the VSim User Guide.

Blocks Contained Within a Field Block

BoundaryCondition (block)

Boundary condition for the field.

InitialCondition (block)

Initial condition for the field.

Source (block)

A source for the field. This is the same as a BoundaryCondition for the field, however may be more useful for introducing a condition over a region of the domain rather than a plane or line as you would expect from a boundary condition.