Volume source of hydrogen negative ions based on reflexive discharge: Theory and experiment (abstract)a

The results of theoretical and experimental studies of the stationary volume source of hydrogen negative ions based on reflexive discharge are presented. Measurements of plasma parameters and emission characteristics are accomplished, and the optimization of ion source geometry is provided. The best parameters of the ion beam extracted from the source across the magnetic field are as follows: current 40 mA, current density—80 mA/cm2, emittance along the magnetic field—3×10−5 cm rad, emittance across a magnetic field—1×10−5 cm rad. The calculation of basic beam properties is performed by numerical solution of the Boltzmann equation for electrons, balance equations for more than 300 elementary processes in gas discharge plasma, and equations of ion and electron motion. The calculated dependencies of hydrogen negative ions’ current density in the plane of emission slit on the gas pressure and the discharge current are found to be in a good agreement with the experimental data.