If Wave 111 was about disciplinary breadth, Wave 112 is about depth in the places where physics gets genuinely hard. Plasmas that tear themselves apart, hearts that fall out of rhythm, energy that refuses to thermalise, and weather that you can never quite predict. Each of these systems is governed by equations that resist neat closed-form answers, which is exactly why an interactive simulation earns its keep: you turn a parameter, and the system surprises you.
Plasma, Pacing and the Edge of Predictability
Three of this wave's headline simulations live right at the boundary between order and breakdown. The plasma instability simulation models how a confined ionised gas develops kink and sausage modes — the same instabilities that plague magnetic-confinement fusion devices like tokamaks. You can watch a column of plasma buckle as the current rises past a critical threshold, and see why holding a star together on Earth is so unforgiving.
The heart rhythm pacing simulation moves the same idea into medicine. Cardiac tissue is an excitable medium, and when wavefronts of electrical activity re-enter and spiral, you get the rotating waves that underlie tachycardia and fibrillation. The simulation lets you trigger a normal sinus rhythm, induce a re-entrant spiral with a mistimed stimulus, and then attempt to reset the tissue with a pacing pulse — a gentle, interactive introduction to why defibrillation works.
Tying these together is the 3D Lorenz attractor, our first fully three-dimensional rendering of Edward Lorenz's 1963 convection model. Watch the trajectory trace its famous butterfly wings, orbiting two unstable fixed points and never repeating. Drag to rotate the attractor in space and adjust the Rayleigh number to see the system slip from steady convection into full deterministic chaos.
Nonlinear Lattices and the FPU Surprise
The Fermi-Pasta-Ulam-Tsingou recurrence simulation revisits one of the most consequential numerical experiments in physics history. In 1955, running on the MANIAC computer at Los Alamos, Fermi, Pasta, Ulam and Tsingou expected a chain of weakly nonlinear springs to share its energy evenly across all modes — thermalisation. Instead, the energy sloshed back almost entirely into the starting mode. The simulation reproduces that near-recurrence directly: seed energy into the first mode, then watch it migrate and mysteriously return. It is widely credited with launching both soliton theory and modern nonlinear dynamics.
For a closely related flavour of complexity, the granular gas simulation models a box of inelastically colliding particles. Because grains lose energy on every bounce, a granular gas behaves nothing like an ideal gas: it cools, clusters, and forms dense streams out of nowhere. It is a vivid demonstration of why sand, grain and powder refuse to obey the tidy thermodynamics taught for molecules.
Fluids, Flames and Spike Trains
The Kelvin wake simulation answers a question every ferry passenger has wondered about: why does the V-shaped wake behind a boat always open at the same angle, regardless of speed? Lord Kelvin showed in 1887 that the half-angle is fixed at roughly 19.47° in deep water, a consequence of how surface gravity waves of different wavelengths interfere. Adjust the vessel's velocity and watch the constructive-interference pattern hold its signature angle.
Turbulent combustion pushes into reactive fluid dynamics, coupling a flame front to a turbulent velocity field. As the turbulence intensity rises, the once-smooth flame wrinkles, folds and accelerates — the corrugated-to-broken-reaction-zone transition that engineers must reckon with in everything from gas turbines to engine knock.
On the biological side, the neural spike train simulation generates and analyses sequences of action potentials. Tune the firing rate and refractory period, switch between regular and Poisson-like firing, and read off inter-spike-interval histograms and raster plots — the bread-and-butter tools of computational neuroscience.
Light in the Sky and Order from Chaos
The wave closes with two simulations devoted to how nature organises itself. Atmospheric optics ray-traces sunlight through ice crystals and water droplets to reproduce haloes, sun dogs, the 22° ring and the rainbow's primary and secondary arcs. Change the crystal orientation distribution and watch which optical phenomena appear.
Crystal growth rounds things off with a diffusion-limited aggregation model. Particles random-walk toward a seed and stick on contact, building dendritic, snowflake-like structures whose fractal dimension you can measure as growth proceeds. It is a quietly mesmerising reminder that intricate order can emerge from nothing more than random walks and a sticky boundary.
Milestone context: Wave 112 is the 112th simulation release on mysimulator.uk. Four of its ten entries — the Lorenz attractor, the FPU lattice, turbulent combustion and the granular gas — are systems where small changes produce outsized, often unpredictable results, making this one of the most chaos-heavy waves yet.
What Comes Next
Wave 113 planning is already in motion. Current candidates include magnetohydrodynamic dynamo action, a Belousov-Zhabotinsky chemical oscillator, reaction-diffusion Turing patterns with live parameter control, and a soliton-collision simulation that builds directly on the FPU work shipped here. The Ukrainian language layer continues to expand in parallel, with translations for all Wave 112 simulations queued for the next content batch.
All ten Wave 112 simulations are live now at mysimulator.uk. If you spot an issue or have a request for a simulation you would like to see, the contact page is always open.