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The Q⊥ volume

The pipeline splits at its natural cost seam. Building the Q⊥ volume means tracing field lines everywhere: minutes-scale, and viewpoint-independent. A render is a line-of-sight integral through that volume: seconds-scale, and different for every camera. So build runs once, and render and qmap reuse the result any number of times.

The .qor cache

build writes a dependency-free .qor (a float32 .npz under the hood) carrying the volume together with its full build provenance: input hash, derived Carrington rotation and Julian date, and every resolved parameter, including the compute backend and precision that produced it. The same details are printed in the end-of-run summary.

Quality

--quality picks the built volume's resolution:

Preset Volume grid Voxels File size
fast 192x180x360 ~12 M ~45 MB
standard (default) 384x360x720 ~100 M ~0.4 GB
high 576x540x1080 ~336 M ~1.1 GB

fast is a quick preview, high resolves the finest structure. Explicit --resolution-factor / --supersample override the preset; indicative build times are in GPU acceleration.

Build flags

The build-time knobs, beyond --quality:

  • --outer-radius: how far out the volume extends, in solar radii (default 12.5). Match it to the product: 8 is comfortable for a whole-corona render at --fov 8, while a Q-map wants the outer radius equal to the map radius.
  • --timestamp, --frame: the observation time (UTC ISO-8601) and the heliographic frame of the solution's longitudes (carrington or stonyhurst; heeq is accepted for Stonyhurst). Neither is in the file; both are baked into the volume and inherited by every product built from it, and together they let the camera take a named observer's viewpoint (see Camera and viewpoint).
  • --closed neutral|dominant: polarity assigned to closed loops, whose two feet have opposite sign (neutral, the default, keeps them neutral; dominant takes the sign of the stronger foot). Read back by the polarity view.
  • --device auto|gpu|cpu and --precision: the compute backend, covered in GPU acceleration.
  • --workers and --quiet: thread count and quiet output, made for batch jobs.

qorona build --help-all is the complete reference (field grid, resampler, tracer tolerances, and more).