v0.1.0

The aurora borealis and australis for Resolume Arena and Avenue, as two FFGL plugins in one download: SW Boreal, a source that is the night sky, and SW Boreal Over, an effect that adds the aurora to your clip as light. An auroral arc is a sheet of electric charge drifting at E×B, and a charge sheet drifting at E×B is a vortex sheet: the potential is a stream function and the space charge its vorticity. So the arc rolls itself up the way a sheet of spinning fluid does, and the curls, folds and westward surge of a substorm are one instability at different scales. Nothing is drawn with a noise function.

Where the sheet winds tight, the field-aligned current is high and, by the Knight relation, so is the electrons' energy. That energy goes into an NRLMSIS atmosphere at the heights Fang et al.'s parameterisation gives, exciting each line by its own chemistry; the green line lives 0.7 s, the red minutes, and low down the red is quenched by collisions first. A camera on a curved Earth looks up through it all. What falls out rather than being arranged: the pink lower border of a hard display, the corona overhead converging on the magnetic zenith, red tops that rise with solar activity, the airglow band low in every long exposure, and snow that goes green under a strong display (Over's Illumination).

What is verified

By tools/verify.sh on an M4 Max, macOS, on 2026-09-24 (all green):

• A single mode on the plugin's own sheet grows at the growth rate derived for its regularised kernel to 2.6e-10 – 8.7e-10 /s at λ = 512, 256 and 128 km.
• Circulation is conserved to 8e-15 over ten minutes; the Hamiltonian's integrator drift shrinks 16× at half the step, as RK4 must.
• E₀ follows the local sheet strength to 1.6e-7 (Knight).
• Ionisation peaks at 118.7 km (1 keV) and 96.7 km (10 keV), against 120 and 97.5 read from Fang 2008's figure.
• The red/green ratio the GPU samples matches the quenching formula at all 721 heights to 1.6e-7; with the flux off the populations decay as e^{−t/τ} to 8e-6 and 5e-5.
• Each spectral line alone sits at its CIE 1931 chromaticity to the fifth decimal.
• Field-aligned rays meet the magnetic zenith to 0.07–0.32 px at 320×180, 640×360 and 1280×720, in both hemispheres.
• The shipped shader's airmass matches Kasten & Young to 9e-7; the airglow brightens as van Rhijn's function to 8e-7.
• Over at Mix 0, or with no light, returns the clip bit-exact; the same seed renders bit-identical frames through a substorm.
• Fourteen deliberately wrong models are all detected, one-character mutations of the shipped GLSL and engine are all caught, and all 39 swept controls change the picture. oxbow loads SW Boreal / BR01 / source and SW Boreal Over / BR02 / effect and renders 120 frames through each.
• CI runs the no-GL half (brtest --offline: the sheet, Knight, deposition, defaults, names, and their negative controls) and compiles every shader with glslc.
• Windows, in Resolume Arena 7.27.1 (win-lab, Mesa llvmpipe, no GPU, 2026-09-24): a CI build of this source loads from Extra Effects, both plugins register with the right id and type, all 43 and 48 host controls match the declaration, both render and Arena's log stays clean: 15 of 15 of the fleet gate's checks, with the audio controls skipped (no sound device). 33 of the source's and 38 of the effect's controls moved the picture; Substorm and Calm are buttons the gate does not press. Software rendering says nothing about a GPU or about speed.

What is not

• Never loaded into Resolume on macOS.
• Some line yields are assumptions: the green is calibrated to about 1 kR per erg, the red and the N₂ first positive are chosen. One lifetime and one vertical shape per line.
• The red haze's wind and diffusion are not checked. At the 4096-node cap the curls stop getting finer (the defaults reach it after about a minute of sky time).
• Render cost is a few to ~10 ms/frame at 720p–1080p at the default Detail on this machine; use Detail Quarter at 4K. No real audio has reached it in a host, so Resolume's 64-bin FFT mapping remains an assumption.
• No OpenFX port. There is a user guide at https://stoatworks-labs.com/software/boreal/guide/ and a browser demo at https://boreal-demo.stoatworks-labs.com.

The macOS build is signed and notarised; the Windows build is unsigned, so SmartScreen warns once. The bundle filenames are Boreal.bundle / Boreal Over.bundle (.dll on Windows); drop both into Extra Effects.