The magnetic field of solar chromospheric spicules

An attractive diagnostic tool for investigating the magnetism of the solar chromosphere is the observation and theoretical modeling of the Hanle and Zeeman effects in solar spicules. Here we highlight the great scientific interest of this new diagnostic window by showing how the magnetic field vector can be inferred from spectropolarimetric observations of solar chromospheric spicules in several spectral lines, such as those of neutral helium and of the oxygen triplet at 777 nm. We may also take the opportunity to clarify the fascinating scattering physics responsible of the polarization observed in spectral lines that stand out in emission when observing just outside the solar limb.