Incident Intensity (Radiative Beam in Absorbing Medium Interface)
Use this node to specify an incident radiative beam on the boundaries of an absorbing medium. The incident beam is defined from its propagation direction and incident intensity. See Absorbing Medium (Radiative Beam in Absorbing Medium Interface) for the modeling of the beam absorption in the medium.
Boundary Selection
Select the boundaries on which to apply the incident beam. The radiative intensity corresponding to the incident beam will be defined on any selected boundary such that the dot product between the beam orientation and the outgoing normal vector from the physics interface selection is negative.
Model Input
This section has fields and values that are inputs to expressions that define material properties. If such user-defined property groups are added, the model inputs appear here.
Beam Orientation
Enter values for the Beam orientation e. The orientation vector does not need to be normalized.
BEAM Profile
Either set the Beam profile as User defined by entering a value for the Deposited beam power density, I0 (SI unit: W/m2), or select an option among the Built-in beam profiles. The Distribution type list provides the following options: Gaussian (the default) or Top-hat disk.
Enter a value for the Deposited beam power P0 (SI unit: W) and the Beam origin point O (SI unit: m).
For Gaussian, enter the Standard deviation σ (SI unit: m).
For Top-hat disk, enter the Beam radius R (SI unit: m). Smoothing can be applied by entering a positive Size of transition zone ΔR (SI unit: m). The default value of 0 m corresponds to an ideal discontinuous top-hat profile.
Upside and downside settings can be visualized by plotting the global normal vector (nx, ny, nz), that always points from downside to upside. Note that the normal vector (ht.nx, ht.ny, ht.nz) may be oriented differently.
See Tangent and Normal Variables in the COMSOL Multiphysics Reference Manual.
Location in User Interface
Context menus
Radiative Beam in Absorbing Media>Incident Intensity
Ribbon
Physics Tab with Radiative Beam in Absorbing Media selected:
Boundaries>Incident Intensity