Ionization of a high energy neutral beam propagating in the ionosphere

By using modeled stripping ionization cross sections and standard atmospheric density models, we calculate stripping ionization probability of high energy (MeV) neutral beams propagating in the earth´s atmosphere. Numerical results as functions of altitude, beam angle and beam energy are presented. We also consider Alfvén´s critical ionization velocity (CIV) process as an alternate ionization pathway. If CIV occurs as the neutral beam propagates through the geoplasma across the ambient magnetic field, it may be an important pathway to rapid ionization halting the beam. We conclude that the parametric conditions are unfavorable for CIV to occur.