Iron in magnetic-field calculations (2)

Our programs PerMag (2D) and Magnum (3D) can handle saturation effects in nonlinear magnetic materials. One of the challenges in calculations with steel is tracking down data for the particular material you are using. In a previous article (http://www.fieldp.com/myblog/?p=15), I discussed how to represent steel at low values of B. Here, the term low means that […]

How much memory do you actually have?

You certainly know how much memory you installed. The issue here is how much memory you can actually use. The question is relevant if you want to solve large technical problems with programs like ours or MatLabĀ®. For this type of software, limitations may arise from the maximum memory that can be allocated to a single […]

Using Aether for eddy current problems

By coincidence, I had two inquiries this week on eddy-current simulations. The first concerned a pulsed valve using a solenoid and iron holding plate. How quickly could the magnetic force be extinguished? The second inquiry was whether Aether could be used to determine the inductance of a 3D magnetic sensor.

I’ll concentrate on the second issue because […]

Resonant frequency and Q of a loaded klystron output cavity

After many benchmark tests and comparisons with theory, I was ready to try Aether on a major production run. The calculation determined the resonant frequency and Q value for the fundamental mode of a loaded klystron output cavity. The three-dimensional solution employed the full range of Aether features included an absorbing boundary. The work is of […]

Let’s make a refrigerator magnet

To illustrate a Magnum calculation of the holding force of a permanent-magnet assembly, what better example than a refrigerator magnet (RM)? Certainly, the mass of RMs in use throughout the world exceeds that of the Large Hadron Collider.

The first picture shows the geometry of a high-quality RM. The magnet is a button of NdFeB with diameter […]