  Theory-based scaling laws of the near and far scrape-off layer (SOL) widths
are analytically derived for L-mode diverted tokamak discharges by using a
two-fluid model. The near SOL pressure and density decay lengths are obtained
by leveraging a balance among the power source, perpendicular turbulent
transport across the separatrix, and parallel losses at the vessel wall, while
the far SOL pressure and density decay lengths are derived by using a model of
intermittent transport mediated by filaments. The analytical estimates of the
pressure decay length in the near SOL is then compared to the results of
three-dimensional, flux-driven, global, two-fluid turbulence simulations of
L-mode diverted tokamak plasmas, and validated against experimental
measurements taken from an experimental multi-machine database of divertor heat
flux profiles, showing in both cases a very good agreement. Analogously, the
theoretical scaling law for the pressure decay length in the far SOL is
compared to simulation results and to experimental measurements in TCV L-mode
discharges, pointing out the need of a large multi-machine database for the far
SOL decay lengths.
