The Application Gallery features COMSOL Multiphysics^{®} tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

Search for tutorials and apps relevant to your area of expertise via the Quick Search feature. To download the MPH-files, log in or create a COMSOL Access account that is associated with a valid COMSOL license. Note that many of the examples featured here can also be accessed via the Application Libraries that are built into the COMSOL Multiphysics^{®} software and available from the *File* menu.

### Self-Demagnetization of a Cylindrical AlNiCo Magnet

Soft permanent magnets like AlNiCo are easily demagnetized if handled incorrectly. This is a demonstration of how to model the self-demagnetization of a cylindrical AlNiCo magnet when moved out of its associated/protective magnetic circuit. The modeling is performed in three steps: 1. The soft magnet protected by the magnetic circuit. 2. The self-demagnetization of the soft magnet when moved ...

### Iron Sphere in a 13.56 MHz Magnetic Field

An iron sphere is exposed to a spatially uniform, sinusoidally time-varying, background magnetic field. The frequency of the field is so high that the skin depth in the sphere is much smaller than the radius. At such high frequencies it is possible to model only the fields and induced currents on the surface of the sphere, thus avoiding the need for solving for the fields within the volume of ...

### Computing Intercepted Flux

This example model demonstrates four different approaches for computing the integrals of fields over arbitrarily placed geometries that can be re-positioned without having to re-solve the model. This approach is also useful if you want to integrate the results of a model over different sub-regions that you do not want to include in your original computational model. The example of computing ...

### Small-Signal Analysis of an Inductor

If an inductor's magnetic material is nonlinear, then the inductance depends on the current passing through it. This model consists of an inductor with a nonlinear magnetic core, where the small-signal inductance is simulated as a function of current. The model also investigates how the small-signal inductance depends on the DC current.

### Simulation of RF Tissue Ablation

This example exemplifies how to model tissue ablation through applying RF radiation. A more detailed description of the phenomenon, and the modeling process, can be seen in the blog post "[Study Radiofrequency Tissue Ablation Using Simulation](/blogs/study-radiofrequency-tissue-ablation-using-simulation/)".

### Contact Impedance Comparison

The contact impedance boundary condition is meant to approximate a thin layer of material that impedes the flow of current normal to the boundary, but does not introduce any additional conduction path tangential to the boundary. This example compares the contact impedance boundary condition to a full-fidelity model and discusses the range of applicability of this boundary condition.

### Capacitance Matrix of Two Spheres

This model compares the numerical and analytical solutions for the capacitance matrix of two nonconcentric spheres. It also illustrates the relation between the Maxwell capacitance matrix and the mutual capacitance matrix.

### Modeling a Capacitive Position Sensor Using BEM

This tutorial model explains how to extract lumped matrices by means of the _Stationary Source Sweep_ study. The capacitance matrix of a five-terminal system is used to infer the position of a metallic object rather like real-world capacitive position sensors. The example illustrates the use of the boundary element method (BEM), which is supported by the _Electrostatics, Boundary Elements_ ...

### Quadrupole Lens

Just like optical lenses focus light, electric and magnetic lenses can focus beams of charged particles. Systems of magnetic quadrupole lenses find a common use in focusing both ion and particle beams in accelerators at nuclear and particle physics centers. This model shows the path of ions going through three consecutive magnetic quadrupole lenses. The model also takes fringing fields ...

### Iron Sphere in a 60 Hz Magnetic Field

An iron sphere is exposed to a spatially uniform, sinusoidally time-varying, background magnetic field. The frequency of the field is low enough such that the skin depth is larger than the radius of the sphere. A reduced field formulation is used to impose the background field. Two approaches for solving this problem are shown. The induced currents in the sphere and the perturbation to the ...