Some boundary conditions, like the Port and Scattering Boundary Condition, provide options for well-defined input fields. If such an input condition is used, it defines the input power variable, ewfd.Pin, where ewfd is the tag of the physics interface.

At boundaries, where the waves leave the simulation domain, such as at the boundaries toward Perfectly Matched Layer domains, or at Port and Scattering Boundary Condition boundaries, the power of the outgoing waves is computed and stored in variables named like ewfd.sctr1.Pout, where sctr1 is the tag of the particular physics feature defined on the boundary. The different output power contributions are then summed up hierarchically with ewfd.Pout representing the total power of all outgoing waves from the physics interface. All output power variables are summarized in Table 2-11.

For the variables ewfd.PoutMPort_N, ewfd.PoutNMPort_N, and ewfd.PoutPort_N, the suffix N represents the value of the Port name parameter for the first Port node listed by the physics on the particular boundary.

The variable ewfd.PoutNMPort_N is always equal to zero, unless the Activate slit condition on interior port checkbox is enabled and Slit type is set to Domain-backed in the Port Settings.

When The Electromagnetic Waves, Beam Envelopes Interface is used, the power variables related to the Wave Equation, Beam Envelopes node are called ewbe.webe1.pml1.Pout and ewbe.webe1.Pout, representing the power flowing from the Wave Equation, Beam Envelopes node webe1 into the Perfectly Matched Layer node pml1 or into all Perfectly Matched Layer nodes overlapping with the Wave Equation, Beam Envelopes node, respectively.

When there is a single feature that provides the input power, it is possible to calculate the coupling of power from that input feature to the different output boundaries. These outcoupling variables form a similar hierarchy as the variables for the power of the outgoing waves. All outcoupling variables are summarized in Table 2-12.

See Table 2-11 for the definition of the variables for the power of the outgoing waves. The suffix N for the Port-related variables, represents the value of the Port name parameter.

For convenience, there are also variables representing scattering loss. With scattering loss means outcoupling through boundaries that almost always represents some sort of unwanted leakage of radiation. The scattering loss variables are summarized in Table 2-13.

To account for absorption in domains and at boundaries, loss variables are defined as listed in Table 2-14.

When the input power variable is defined, it is possible to define the absorptance for each lossy feature and for the total absorptance. The different absorptance variables are summarized in Table 2-15.