The dynamics and heating of the quiet solar chromosphere

The solar chromosphere can be characterized by two signatures: the spectros copic signature is an emission spectrum for all radiation originating in th e chromosphere; only NLTE effects in the cores of strong lines producing ab sorption features. And the dynamical signature is in the form of oscillatio ns, with a period of 3 min in the nonmagnetic chromosphere and a period of 7 min in magnetic regions. The paper explains these signatures in terms of waves: The dynamics of the chromosphere is due to acoustic waves in the magnetic-field-free atmosphere , which produce K-2v bright points, and to kink and longitudinal waves in m agnetic flux tubes, which produce network bright points. The heating of the chromosphere is caused by acoustic waves whose dissipation makes the kinet ic temperature rise in the outward direction, producing the emission spectr um. As far as energy fluxes are concerned, the energy dissipated in chromos pheric heating outweighs the energy visible in bright points by two orders of magnitude, The paper interprets the observed oscillation periods in the chromosphere a s cutoff periods: for the 3 min period, as the cutoff period of acoustic wa ves in a nonmagnetic, stratified atmosphere; and for the 7-min period, as t he cutoff period of kink waves in magnetic flux tubes for field strengths t ypical of the magnetic network.