Electric Shielding Comparison
The electric shielding boundary condition is meant to approximate a thin layer of highly conductive material that provides an additional current path tangential to a boundary. This example compares the electric shielding boundary condition to a full-fidelity model and discusses the range of applicability of this boundary condition.
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 ...
Electric Shielding
Many applications involve simulating the electromagnetic behavior of relatively thin material in voluminous domains. To save computer memory and processing time, the thin materials can be treated differently by resolving them with 3D meshes. Here, the modeling domain is a box filled with air containing an electrode. The sides of the box are insulated while the top has a potential and the ...
Electrodynamic Bearing
This model illustrates the working principle of a passive electrodynamic bearing. An electrically conducting rotor rotating in a magnetic field produced by a permanent magnets induces eddy currents on the conducting rotor. The eddy currents, in turn, produce a magnetic field that opposes the magnetic fields by the magnets and induces a force that opposes the motion of the rotor. The radial ...
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 ...
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.
Thin Low Permittivity Gap Comparison
The thin low permittivity gap boundary condition is meant to approximate a thin layer of material with low relative permittivity compared to its surroundings. This boundary condition is available for electrostatic field modeling. This example compares the thin low permittivity gap boundary condition to a full-fidelity model and discusses the range of applicability of this boundary condition.
Quadrupole Mass Filter
A quadrupole mass filter (QMF) is a key component of a modern mass spectrometer. A QMF uses direct current (DC) and alternating current (AC) electric fields to analyze positive or negative ions by mass to charge ratio. A QMF consists of 4 parallel rods spaced equidistantly, the ratio of the rod radius to the radius of the inscribed circle is 1.148. Opposite pairs of rods are electrically ...
Ion Funnel
An electrodynamic ion funnel provides an efficient means of transferring ions from regions of high pressure to high vacuum. The ion funnel can couple devices which generally operate at pressures of different orders of magnitude, such as ion mobility spectrometers and mass spectrometers, allowing mixtures of ionized gases to be separated and analyzed while minimizing losses. This model ...
Characteristic Parameters of a Coaxial Cable
Electrical cables, also called transmission lines, are used everywhere in the modern world to transmit both power and data. These cables carry electromagnetic energy, but instead of dealing with the full complexity of the electromagnetic fields, they are more commonly classified according to parameters such as capacitance, inductance, and impedance. In this model of a coaxial cable, we ...
