Remanenza: Magnetic Hysteresis Loop
Electromagnetism & Plasma arc, page 87 of 193. Back to The Pixelated Physics Universe
Who they are
Remanenza has one line, and says it often: “Full revision loop. area lost as heat.”
Remanenza is a character of the Electromagnetism & Plasma arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
Hysteresis: the area enclosed by a B–H loop equals the energy dissipated per cycle per unit volume.
$$ \begin{gathered} W = \oint H \, dB \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $W$ | energy dissipated per cycle per unit volume | J/m^3 |
| $H$ | magnetic field strength | A/m |
| $B$ | magnetic flux density | T |
Sources
- E. Warburg, "Magnetische Untersuchungen", Ann. Phys. 249, 141 (1881)
- C. P. Steinmetz, "On the law of hysteresis", Trans. AIEE 9, 1 (1892)
Crossovers
Remanenza meets Quenchard (Superconducting Magnet Quench). Quenchard dumps a magnet's stored energy, ½LI², when a spot goes normal. Remanenza's hysteresis loss is quieter: each cycle of a magnetic material dissipates energy equal to the loop area.
Remanenza meets Magnetron Twins (Electromagnetism / Polarity Lock). The Magnetron Twins line up their electron spins through exchange. Remanenza remembers the field that lined them up: drive the field back to zero and some magnetisation stays, which traces out a hysteresis loop.
Remanenza meets Ayrtha (Hertha Ayrton, the Electric Arc and Sand Ripples). Ayrtha studied the electric arc, whose voltage and current don't follow a simple straight-line law. Remanenza's hysteresis is another case where a material's response depends on its history, not just on the present input.
Wear the lore
Concept keywords: Magnetic Hysteresis Loop, Remanenza, Electromagnetism & Plasma, physics lore, Pixelated Physics