Verification and Validation of Low-Temperature Plasma Modeling in Ansys Charge Plus
Plasma isn’t just glowing gas in sci-fi movies; it quietly powers modern technology. From the chips in your phone to the behavior of spacecraft, engineering applications increasingly rely on understanding plasma, a state of matter made up of ionized particles. Capturing its behavior accurately requires simulation tools that can keep pace with complex multiphysics interactions.
“Simulation becomes an integral part of engineering only when we can demonstrate its accuracy,” Electro Magnetic Applications, Inc. (EMA) Senior Scientist Gregory Wilson said. “Verification and validation are essential steps before any engineer should trust a plasma model.”
Verification and validation efforts are underway for new low-temperature plasma simulation capabilities in Ansys Charge Plus. In this article, you will get a closer look at:
- Plasma applications and simulation
- Why verification and validation matter
- Verification benchmarks
- Validation benchmarks
Advancing Semiconductor Fabrication Through Plasma Simulation
Plasma tools are becoming essential for industrial and research system design.
Industrial applications driving demand are:
- Semiconductor plasma etching
- Plasma enhanced chemical vapor deposition (PECVD)
- Ion beam processing
- Atmospheric plasma treatment
- Fusion and research devices
- Plasma thrusters
Ansys Charge Plus supports these workflows by simulating plasma interactions, electrical charging, discharging, and electrostatic discharge (ESD) in realistic multiphysics environments. By modeling ions and electrons at the kinetic level, it captures effects that fluid-based approaches often miss, including sheath formation, transient plasma behavior, and surface charge buildup. These detailed insights help engineers analyze how particles respond to external fields, interact with materials, and evolve over time, critical pieces for understanding semiconductor processing and any technology dependent on precise control of low-temperature plasmas.
Why Verification and Validation Matter
Modern plasma simulation is a deeply interconnected problem: electromagnetic fields, charged particles, reactions, collisions, and temperature all influence each other within complex geometries. Without careful verification and validation, simulation results may look plausible while being physically incorrect, leading to failed designs, inaccurate predictions, or expensive rework.
Verification vs. Validation
Verification tests the code against analytic behavior, while validation tests the model against reality.
“In verification, we’re not checking the data, we’re checking the mathematics,” Wilson said.
This involves:
- Testing code behavior against analytic solutions
- Using intentionally simplified test problems
- Examining isolated physics modules
- Ensuring numerical methods behave as expected
Verification is about coding correctness, not physical realism.
“Validation is where we make sure the model is physically accurate for what we want to simulate,” Wilson continued.
This involves:
- Comparing simulation results with experimental measurements
- Running established benchmark cases
- Evaluating interactions across coupled physics
Validation demonstrates that Charge Plus behaves like the real-world plasma it is designed to model.
Both steps are essential: verification ensures the engine runs correctly; validation ensures the car drives straight.
From Simple to Sophisticated
To ensure the physics engine performs reliably across the full range of plasma simulation scenarios, EMA uses a layered verification and validation strategy. Each layer builds on the previous one, starting with isolated physical effects and progressing toward full multiphysics reactor environments. This approach minimizes uncertainty, catches foundational issues early, and demonstrates accuracy under increasingly complex conditions.
Simple Benchmark Cases: These tests isolate a single physical phenomenon to ensure Charge Plus handles fundamental physics properly.
Intermediate Coupled Phenomena: The model is tested with multiple interacting physics to validate that Charge Plus handles dynamic, realistic conditions, not just isolated equations.
Full System Simulations: The team verifies full-geometry, full-physics cases. At this stage, Charge Plus must deliver accuracy across the entire multiphysics spectrum.
Key Verification Benchmarks
Particle Acceleration
To confirm the solver behaves correctly under strong electric fields, engineers verify that particle acceleration matches theoretical predictions. They compare:
- Growth of kinetic energy over time
- Velocity changes as particles move through space
- Accuracy of field interpolation
- Agreement with analytic benchmark solutions
The results show Charge Plus consistently delivers results within ~1% of theoretical values, confirming precise and stable particle dynamics.
Fig. 1. Results show particles accelerating through the electric field gaining velocity and energy, confirming the expected physical behavior in the simulation.
Landau Damping
Landau damping is a subtle plasma effect where oscillations naturally decrease due to particle-wave interactions. To validate that Charge Plus captures this behavior correctly:
- A controlled sinusoidal perturbation is introduced
- Engineers track how the oscillation amplitude evolves
- Mode behavior is examined in phase space
- Results are checked against expected theoretical rates
Charge Plus accurately reproduces the expected damping behavior while keeping numerical noise low, demonstrating strong fidelity in capturing foundational plasma physics.
Fig. 2. Phase-space view of Landau damping. The electron oscillations gradually lose energy as wave-particle interactions smooth out the motion.
Key Validation Benchmarks
After verifying the mathematics, the team moved on to validation, where Charge Plus is tested against experimental results to ensure its physical accuracy.
1D DC Glow Discharge
Charge Plus is compared against well-established experimental behavior to confirm that the underlying physics are correctly reproduced. This classic benchmark evaluates:
- Plasma density
- Sheath structure
- Voltage distribution
The simulation accurately reproduced the expected 1D DC glow discharge. Plasma structure, electron density, sheath thickness, and breakdown behavior all align with reference data, including a breakdown-voltage comparison that tracks closely with established experimental values.
Fig.3. 1D DC glow discharge simulation using Ar. It shows the classic plasma structure and sheath formation across the gap, validating expected discharge behavior.
3D Capacitive Coupled Plasma
This benchmark demonstrates Charge Plus’s ability to handle realistic, industrial plasma environments. The simulation is evaluated against:
- Breakdown voltages
- Discharge uniformity
- Reactor field patterns
The 3D CCP model shows strong agreement with GEC (Gaseous Electronics Conference) reference data, accurately capturing plasma structure, sheath formation, electron energy distributions, and RF-driven breakdown behavior.
“Our validation benchmarks show Charge Plus behaves like the physical system it represents,” Wilson said.
Fig. 4. 3D CCP simulation showing the dynamic evolution of plasma density and sheath formation as the RF field drives the discharge.
What’s Next for Plasma Simulation
Charge Plus continues to advance rapidly, with upcoming improvements such as broader benchmark coverage, full-3D full-wave electromagnetic plasma modeling, refined numerical damping, and more robust energy-conserving time-stepping schemes. EMA is also pushing stability in extreme plasma regimes and expanding support for increasingly complex reactor geometries.
“Plasma tools are becoming more essential as simulations grow more complex,” Wilson said. “These benchmarks let us isolate physics so it’s easy to troubleshoot and verify they’re working.”
Ongoing verification and validation ensure Charge Plus remains a reliable, forward-looking solution as plasma engineering evolves. To explore the methodology and results in depth, check out the EMA Expo 2026 session “Verification and Validation of Plasma Multiphysics Simulations,” available on demand here.
If you’re ready to see how these capabilities can elevate your workflows, contact EMA to request a demo and learn how our plasma modeling expertise can accelerate your plasma projects.
