Electrode
The Electrode multiphysics node () sets the electric field and an electric potential at a given boundary defined in the selection of this feature. The normal component of the electric field is set to a given value E0 at the boundary selection
(9-1)
and is used as a boundary condition to Poisson’s equation solved in the Electrostatics interface. The charge density from the Charge Transport interface at the boundary selection is found using a Lagrange multiplier to verify
(9-2)
where V0 is a given electric potential.
Electric Potential
This is the value of the electric potential to be applied in the selected boundary. In the Electric potential V0 (SI unit: V) field enter a value or expressions for the electric potential.
Electric Field
Select an option from the Electrode electric field list — Peek’s Law (the default) or User defined. When Peek’s Law is selected this section has the following fields that are used to compute the electric field using Peek’s Law:
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Enter a Disruptive electric field Ec (SI unit: V/m).
•
Enter an Empirical constant c (SI unit: m1/2).
•
Enter an Electrode radius rc (SI unit: m).
If Electrode electric field is set to User defined enter a value or expression for the Electric field E0 (SI unit: V/m).
Coupling features are available from the context menu (right-click the Multiphysics Couplings node) or from the Physics toolbar, Multiphysics menu.
If a physics interface is deleted and then added to the model again, and in order to reestablish the coupling, you need to choose the physics interface again from the lists. This is applicable to all multiphysics coupling nodes that would normally default to the once present physics interface. See Multiphysics Modeling Workflow in the COMSOL Multiphysics Reference Manual.