Optical excitation and ionization of fast hydrogen atoms

The possibility is considered of increasing the efficiency of injecting fast hydrogen atoms into a magnetic trap, by the following methods.

1. Increasing the population of the upper levels (n ≈ 10) in a beam of fast hydrogen ions by irradiating them with quanta which are resonant with a chosen n₁l₁ → n₂l₂ transition, for example 2s → 10p. The dependence is found of the population of the n₂l₂ level on the radiation density and the transit time of the atoms in the radiation field. An estimate of the power of the light source required is made on the basis of the data obtained.

2. Photo-ionization of the hydrogen atoms directly in the active region of the trap. On the basis of the calculated dependence of the magnitude of the photo-ionization cross section of the H-atom on the wavelength of the radiation, an estimate is made of the power of the light flux needed for effective ionization of the atoms.