  The atmospheric neutrino flux at very high energies is dominated by prompt
neutrinos, mostly contributed by the decays of charmed hadrons produced in the
forward direction by cosmic ray interactions with air nuclei. Theoretical
predictions of the prompt atmospheric neutrino flux have large uncertainties
mainly related to charm hadron production. Prompt neutrinos can also be studied
through high-energy colliders. In particular, two ongoing forward experiments
and the proposed Forward Physics Facility at the LHC can detect forward prompt
neutrinos. We will present the kinematic regions relevant to the prompt
atmospheric neutrino flux in terms of collider kinematic variables, the
collision energy $\sqrt{s}$ and the center-of-mass rapidity of charm hadrons
$y$, and discuss implications of the forward experiments at the LHC on the
theoretical predictions of the prompt atmospheric neutrino flux.
