• Description

Plasma Module Updates

For users of the Plasma Module, COMSOL Multiphysics ® version 5.2a brings reorganized plasma physics interfaces for more efficient model setup and workflow, including the ability to seamlessly couple multiphysics interfaces in your plasma simulation, as well as a new Domain Terminal feature for geometrically complex electrodes.

Reorganization of Plasma Physics Interfaces

In COMSOL Multiphysics ® version 5.2a, the DC Discharge and Capacitively Coupled Plasm a interfaces have been replaced with a new interface called Plasma . The Plasma interface includes all of the functionality of theDC Discharge and Capacitively Coupled Plasma interfaces. Upon opening a model containing the DC Dischargeand Capacitively Coupled Plasma interfaces, it is automatically converted to the new Plasma interface. However, to provide backward compatibility, the original interface Label, Name, and Tag are retained.

The Inductively Coupled Plasma and Microwave Plasma interfaces have been reimplemented as multiphysics interfaces combining the Plasma and Magnetic Fields interfaces, and the Plasma and Electromagnetic Waves, Frequency Domain interfaces, respectively. The table below summarizes these changes.

Old Interface Name (Before Version 5.2a) New Interface Name(s)

DC Discharge

Plasma

Capacitively Coupled Plasma

Plasma

Inductively Coupled Plasma

  • Plasma
  • Magnetic Fields
  • Inductively Coupled Plasma (multiphysics coupling)

Microwave Plasma

  • Plasma
  • Electromagnetic Waves, Frequency Domain
  • Microwave Plasma (multiphysics coupling)

Coupling between the high-frequency fields and plasma for the Inductively Coupled Plasma and Microwave Plasma interfaces is now done using multiphysics coupling features. Using cold plasma approximation, thePlasma Conductivity Coupling multiphysics interface computes the electric conductivity required by theMagnetic Fields and Electromagnetic Waves, Frequency Domain interfaces based on the electron density, collision frequency, and angular frequency. The Electron Heat Source multiphysics interface computes the collisional heating of electrons based on the plasma conductivity and electric field.

As an example, when adding the Microwave Plasma interface in the Model Wizard, the following appears:

The Model Wizard after adding the new Microwave Plasma interface.

The Model Wizard after adding the new Microwave Plasma interface.

Similarly, when adding the Inductively Coupled Plasma interface, the following appears:

The Model Wizard after adding the new Inductively Coupled Plasma interface.

The Model Wizard after adding the new Inductively Coupled Plasma interface.

Backward Compatibility

The old Inductively Coupled Plasma and Microwave Plasma interfaces can still be opened, edited, and solved. When such a model is opened, a warning is given indicating that the interface is obsolete and will eventually be removed.

Domain Terminal

You can now use the Terminal feature in the Electric Currents and Electrostatics physics interfaces on the domain level. This is convenient for geometrically complex electrodes that would involve the selection of a large number of boundaries when using a terminal at the boundary level. The unknowns for the electric potential inside the terminal's domain selection are not solved for, but rather replaced by a variable. This is useful when modeling electrodes with a finite thickness that is respected by the geometry.

The Capacitor Tunable model in the AC/DC Application Library has been updated to use the new domain terminal, reducing the selection from more than 50 boundaries to a single domain.
The Capacitor Tunable model in the AC/DC Application Library has been updated to use the new domain terminal, reducing the selection from more than 50 boundaries to a single domain.