In 1953 Olle Karlqvist (Sweden) discovered a fundamental magnetic phenomenon when he was designing a magnetic storage

Magnetic storage

Magnetic storage and magnetic recording are terms from engineering referring to the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetization in a magnetizable material to store data and is a form of non-volatile memory. The information is accessed using...

 and the ferromagnetic surface layer to the magnetic drum memory for the BESK

BESK

BESK was Sweden's first electronic computer, using vacuum tubes instead of relays. It was developed by Matematikmaskinnämnden and during a short time it was the fastest computer in the world. The computer was completed in 1953 and in use until 1966...

computer. When designing a magnetic memory store you have to study the ferromagnetic layer and the variation of this field with permeabliity, airgap, layer thickness and other influencing factors. The problem is definity non-linear and extremely difficult to solve. Karlqvist gap discovery shows that non-linear could be solved in a linear boundary value for the two-dimensional staic field and the one-dimensional transient field. This linear calculation gives a first approximation, which in some case seems to be satisfacory. He published his discovery Calculation of the magnetic field in ferromagnetic layer of a magnetic drum at Royal Institute of Technology (KTH).

The magnetic phenomenon discovered is nowadays called the Karlqvist Gap or Karlqvist Field.