electromagneticSource

Specify charge density on the entire geometry for an electrostatic analysis.

emagmodel = createpde("electromagnetic","electrostatic");
importGeometry(emagmodel,"PlateHoleSolid.stl");
electromagneticSource(emagmodel,"ChargeDensity",10)

ans = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Cell'
          RegionID: 1
     ChargeDensity: 10
    CurrentDensity: []
     Magnetization: []

Specify current density on the entire geometry for harmonic analysis.

Create an electromagnetic model for harmonic analysis.

model = createpde("electromagnetic","harmonic");

Include a square geometry in the model. Plot the geometry with the edge labels.

geometryFromEdges(model,@squareg);
pdegplot(model,"EdgeLabels","on")
xlim([-1.1 1.1])
ylim([-1.1 1.1])

Specify current density on the entire geometry. For a 2-D harmonic analysis model with the electric field type, the current density must be a column vector of two elements. When solving the model, the toolbox multiplies the specified current density value by -i and by frequency.

electromagneticSource(model,"CurrentDensity",[1;0])

ans = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Face'
          RegionID: 1
     ChargeDensity: []
    CurrentDensity: [2x1 double]
     Magnetization: []

Specify charge density on individual faces in electrostatic analysis.

Create an electromagnetic model for electrostatic analysis.

emagmodel = createpde("electromagnetic","electrostatic");

Create a 2-D geometry with two faces. First, import and plot a 2-D geometry representing a plate with a hole.

gm = importGeometry(emagmodel,"PlateHolePlanar.stl");
pdegplot(gm,"EdgeLabels","on","FaceLabels","on")

Then, fill the hole by adding a face and plot the resulting geometry.

gm = addFace(gm,5);
pdegplot(gm,"FaceLabels","on")

Specify charge density values separately for faces 1 and 2.

sc1 = electromagneticSource(emagmodel,"Face",1,"ChargeDensity",0.3)

sc1 = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Face'
          RegionID: 1
     ChargeDensity: 0.3000
    CurrentDensity: []
     Magnetization: []

sc2 = electromagneticSource(emagmodel,"Face",2,"ChargeDensity",0.28)

sc2 = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Face'
          RegionID: 2
     ChargeDensity: 0.2800
    CurrentDensity: []
     Magnetization: []

Use a function handle to specify a charge density that depends on the coordinates.

Create an electromagnetic model for electrostatic analysis.

emagmodel = createpde("electromagnetic","electrostatic");

Create a unit circle geometry and include it in the model.

geometryFromEdges(emagmodel,@circleg);

Specify the charge density as a function of the x- and y-coordinates, $\rho =0.3\sqrt{{\mathit{x}}^2+{\mathit{y}}^2}$.

rho = @(location,~)0.3.*sqrt(location.x.^2 + location.y.^2);
electromagneticSource(emagmodel,"ChargeDensity",rho)

ans = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Face'
          RegionID: 1
     ChargeDensity: @(location,~)0.3.*sqrt(location.x.^2+location.y.^2)
    CurrentDensity: []
     Magnetization: []

Use a solution obtained by performing DC conduction analysis to specify current density for a magnetostatic model.

Create an electromagnetic model for DC conduction analysis.

emagmodel = createpde("electromagnetic","conduction");

Import and plot a geometry representing a plate with a hole.

gm = importGeometry(emagmodel,"PlateHoleSolid.stl");
pdegplot(gm,"FaceLabels","on","FaceAlpha",0.3)

Specify the conductivity of the material.

electromagneticProperties(emagmodel,"Conductivity",6e4);

Apply the voltage boundary conditions on the left, right, and back faces of the plate.

electromagneticBC(emagmodel,"Voltage",0,"Face",[1 3 5]);

Specify the surface current density on the front face of the geometry and on the face bordering the hole.

electromagneticBC(emagmodel,"SurfaceCurrentDensity",100,"Face",[2 7]);

Generate the mesh.

generateMesh(emagmodel);

Solve the model.

R = solve(emagmodel);

Change the analysis type of the model to magnetostatic.

emagmodel.AnalysisType = "magnetostatic";

This model already has a quadratic mesh that you generated for the DC conduction analysis. For a 3-D magnetostatic model, the mesh must be linear. Generate a new linear mesh. The generateMesh function creates a linear mesh by default if the model is 3-D and magnetostatic.

generateMesh(emagmodel);

Specify the current density for the entire geometry using the DC conduction solution.

electromagneticSource(emagmodel,"CurrentDensity",R)

ans = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Cell'
          RegionID: 1
     ChargeDensity: []
    CurrentDensity: [1x1 pde.ConductionResults]
     Magnetization: []

Specify magnetization on a face in a magnetostatic analysis.

Create a unit square geometry with a circle in its center. The circle represents a permanent magnet.

L = 0.8;
r = 0.25;
sq = [3 4 -L L L -L -L -L L L]';
circ = [1 0 0 r 0 0 0 0 0 0]';
gd = [sq,circ];
sf = "sq + circ";
ns = char('sq','circ');
ns = ns';
g = decsg(gd,sf,ns);

Plot the geometry with the face labels.

pdegplot(g,"FaceLabels","on")

Create a magnetostatic model and include the geometry in the model.

emagmodel = createpde("electromagnetic","magnetostatic");
geometryFromEdges(emagmodel,g);

Specify the magnetization magnitude.

M = 1;

To make the circle represent a permanent magnet, specify the uniform magnetization in the positive x-direction.

electromagneticSource(emagmodel,"Face",2,"Magnetization",M*[1;0])

ans = 
  ElectromagneticSourceAssignment with properties:

        RegionType: 'Face'
          RegionID: 2
     ChargeDensity: []
    CurrentDensity: []
     Magnetization: [2x1 double]