Polarity view

The squashing-factor render coloured by magnetic polarity: --polarity-mode hue paints outward field warm, inward field cool, and white where opposite polarities cancel along the line of sight, so open-field cells of opposite sign and the current sheet between them are read at a glance.

qorona render data/coconut_corona.qor -o data/polarity.png \
    --fov 8 --longitude 317 --latitude 6.2 --polarity-mode hue

The flags that matter

• --polarity-mode hue: warm = outward, cool = inward; none (the default) is the plain render.
• The polarity sign is stored in the volume, so the closed-loop treatment is chosen at build time: qorona build --closed neutral|dominant. An open line takes the sign of B·r̂ at its single photospheric foot; a closed loop has two feet of opposite sign, so it has no single rooting polarity. neutral (the default) keeps closed loops white, separating open from closed field at a glance; dominant takes the sign of the stronger foot.
• Camera and display flags are the same as the squashing-factor render.