NdFeB Magnet: Field, Force & Thermal Demagnetization (2D)

This 2D companion swaps the original's abstract sintering-plant animation for the physics of the finished magnet itself: two NdFeB discs face each other across an adjustable air gap, and every number on screen — axial force, on-axis field strength at the gap, magnetic moment, and the split between reversible and irreversible flux loss with temperature — comes from a real magnetic-dipole force law and a grade-specific thermal model, not a scripted readout. Switch grades (N35/N42/N52), flip the facing to compare attraction against repulsion, and push the temperature past a grade's rated maximum to watch permanent demagnetization accumulate — only the "Re-magnetize" button can undo it, matching how real sintered NdFeB behaves once it crosses its knee point.