Ryabtsev A. Kinetic processes in the hydrogen negative ion source with reflective discharge.

This thesis is dedicated to a comprehensive investigation of the hydrogen negative ion source with the reflective discharge. For the first time, the theory which takes into account all significant physical processes occurring in the source was developed. Using this theory, the influences of the discharge specific power and pressure in the source on its main characteristics were studied. The differences in the growth rate of hydrogen negative ion concentration for variation discharge current was explained. Based on the examination of differences in the temporary dependences of the plasma component concentrations, the conclusion about the possibility of an increase of the negative ions concentration in the pulse-periodic regime was made. For the first time, the plasma component distribution in the gap between the discharge column and the anode was obtained. The distribution obtained for negative ions was essentially non-monotonous that results in the existence of the optimum ratio of anode and dischargecolumn radiuses. The influence of cesium on the processes in the negative hydrogen ion source was also studied. From the experimental results as well as from the numerical calculation it follows, that during the addition of cesium to the discharge the major portion of negative ions is formed at the surface of the source rather than in its volume. In this case the current of negative ions extracted form the source increases by a factor of 2?3.