Tools for 3D solar magnetic field measurement

We review the various plasma conditions occurring in the photosphere, chromosphere, and corona, which determine the different regimes of atomic excitation of these regions.

Depending on the relative importance of anisotropic irradiation of the gas over collisional thermalization of the atomic populations, the description of the atomic excitation states may necessitate a full quantum-statistical treatment, which exacerbates the numerical complexity of an already computationally intensive problem. Special emphasis is placed on forward modeling and inversion techniques that mitigate this difficulty, making feasible the interpretation of polarization signals in terms of the magnetic field and its connectivity throughout the solar atmosphere.