Chromosféru

Chromosféru, also known as the chromosphere, is a layer of the Sun’s atmosphere situated above the photosphere and below the corona. It extends roughly 2,000 to 3,000 kilometers above the visible solar surface and exhibits a temperature rise from about 4,000 kelvin at its base to around 8,000 kelvin with height. The chromosphere is most easily observed in certain spectral lines, notably the hydrogen-alpha line and the calcium II H and K lines, where it appears as a reddish rim around the solar disk or as a bright halo at the limb during eclipses.

The chromosphere is highly structured by magnetic fields and hosts a range of dynamic features. Spicules—jets of plasma that rise from the surface—can reach about 5,000 to 10,000 kilometers above the surface and typically last several minutes. Other features include fibrils and plages, as well as larger-scale structures such as filaments and prominences, which trace magnetic activity and can appear on the disk or at the limb.

Physically, the chromosphere is not in local thermodynamic equilibrium, and radiative transfer in this layer is complex. Its energy balance and heating mechanisms are active research topics, with waves, magnetic fields, and reconnection processes contributing to the transport of energy toward the outer solar atmosphere.

Observations of the chromosphere are conducted with ground-based solar telescopes and space-based instruments, using spectroscopy and imaging in H-alpha, Ca II lines, and other wavelengths. Studying the chromosphere helps researchers understand solar magnetic activity, mass and energy transport, and the broader problem of coronal heating.