Evolution of chromospheric spicules.

The author has studied the question of whether the line-of-sight velocity, detected in spicules, indicates real motions along their axes, or whether they are transverse motions only. The answer to this question requires direct methods, such as the one of investigating the spectrum of spicules continuum radiation, resulting from photospheric light scattering. Until now only investigations of emission line profiles have indicated that some properties of spicules could be understood from the models of nonexpanding supersonic jets.