COMSOL Multiphysics^® 6.2 Release Highlights

Plasma Module Updates

For users of the Plasma Module, COMSOL Multiphysics^® version 6.2 provides the ability to use the Frequency-Stationary study step for microwave plasma models, a new Reaction Group feature to easily add chemical reactions to plasmas, and the ability to solve heavy species energy conservation in global models. Browse all of these updates below.

Increased Stability for Microwave Plasmas

It is now possible to implement the Frequency-Stationary study step in microwave plasma models, significantly reducing computational time. This formulation uses a combination of solver settings and parameterizes the input power of the plasma reactor instead of its deposited power, resulting in more stable microwave plasma models. You can see this study step in use in the new Microwave Cavity Plasma Reactor and updated Dipolar Microwave Plasma Source tutorial models.

A microwave plasma reactor operating in hydrogen from the new Microwave Cavity Plasma Reactor model.

Reaction Group

A new Reaction Group feature allows for the input of a large number of heavy species reactions in a table, making it easier to add chemical reactions to plasmas. The inputs can be added manually, imported from a file, or added automatically using the Plasma Chemistry add-in. The Microwave Cavity Plasma Reactor tutorial model uses this feature to add reactions involving atoms and molecules of hydrogen.

Heavy Species Energy Conservation Equation in Global Models

In version 6.2, the heavy species energy conservation equation can now be solved in global models defined by ordinary differential equations, or ODEs. This functionality can be used to study the effect of the gas temperature when testing plasma chemistry with a zero-dimensional, or ODE, approach. There are also options for evaluating the temperature of the feed gas and the heat transferred to surfaces. You can see this update in the new Hydrogen Global Model Coupled with the Two-Term Boltzmann Equation tutorial model.

New Tutorial Models

COMSOL Multiphysics^® version 6.2 brings the following new tutorial models to the Plasma Module.

Microwave Cavity Plasma Reactor

The Microwave Cavity Plasma Reactor model solves for a hydrogen plasma sustained in a microwave cavity at moderate pressures. This model solves the plasma transport equations, which are fully coupled with Maxwell’s equations, fluid flow, and heat transfer. A microwave cylindrical chamber contains a bell jar where a hydrogen plasma is created. The reactor is carefully designed so that the electric field has its maximum intensity above a substrate and much lower intensity at the bell jar boundary. This design is needed in order for the plasma to keep its maximum density in the substrate region even at high power.

Application Library Title:
microwave_cavity_plasma
Download from the Application Gallery

Hydrogen Boltzmann Analysis

The Hydrogen Boltzmann Analysis model shows the electron energy distribution function (EEDF) in the high-frequency limit and as time averaged. The model also demonstrates the EEDFs for time instants corresponding to the most depleted and populated tail. The simulations are performed for hydrogen at 25 kPa with a reduced electric field of 50 Td (Townsend) at 2.45 GHz.

Application Library Title:
boltzmann_hydrogen
Download from the Application Gallery

Hydrogen Global Model Coupled with the Two-Term Boltzmann Equation

The Hydrogen Global model demonstrates the electron energy distribution function (logarithm base 10) as a function of the electron energy parameterized for the power absorbed by the plasma. In this model, the Boltzmann equation in the two-term approximation is solved self-consistently with a global model for a hydrogen plasma that includes the heavy species heat equation.

Application Library Title:
hydrogen_global_model
Download from the Application Gallery