The Princeton Dee magnet

The Princeton Dee is one of the canonical idealized shapes for tokamak toroidal field (TF) magnets. Since increasing the magnetic field is so important for tokamak performance, the TF magnets are subject to extreme engineering: I’ve heard an engineer refer to them as “the most highly structural member ever built”. Energizing the magnet creates a... Read more 28 Feb 2021

Polar form for an ellipse offset from the origin

I recently needed a polar-form equation for an ellipse, where the center of the ellipse is offset from the origin. I couldn’t easily find such an equation, so I derived it and am posting it here. (It’s easy to find expressions for ellipses where the focus is at the origin.) Read more 16 Feb 2021

Scaling of relative neutron fluxes at inboard and outboard midplane with aspect ratio

The most intense neutron flux in a tokamak is normally found at the midplane. The flux on the inboard side is often a critical value, since inboard space is scarce. The magnets need to be shielded so that they remain operational for the lifetime of the machine, but extra shielding thickness is wasted space. Read more 06 Feb 2021

Magnetic field at the surface of a long conductor with a square cross section

Assume an infinite conductor with a square cross-section. It has side length $l$ and carries a current along its length with uniform density $J$. Read more 21 Oct 2020

OpenRCT2 operations research: how many mechanics should I hire?

OpenRCT2 breathes new life into a classic game Read more 31 Aug 2020