Solar flares are gigantic ejections of charged gas that rush along magnetic highways. Using spectral analysis (spectroscopy) and brightness measurements (photometry), the Hinode satellite found that heavy iron ions, visitors from ancient supernovae, race almost exclusively along the field lines. Like cars on a highway, they rarely veer onto the shoulder.

By measuring the width of spectral lines, scientists applied the effect of Doppler (here speed of light is crucial). At the center of the solar disk, the lines were broad — ions moving toward or away from us. At the edges, where the field is directed across the line of sight, the lines are narrower. So the main motion is along the field. This is not like a chaotic explosion: energy does not dissipate instantly, as predicted by classical models from Maxwell and Boltzmann with their increasing entropy.

Even five minutes after the flare peak, the Fe XIV iron spectral band remains anomalously broad — the plasma continues to 'boil,' as if heated from within. This prolonged order is important for understanding stellar activity that threatens the atmospheres of exoplanets. And the iron itself is a reminder: we are made of stardust, which still burns in the Sun, in its hydrogen-helium plasma (hydrogen and helium).