Registration of accelerated multiply charged ions from the cathode jet of a vacuum discharge

The parameters of Cuⁿ⁺ and Taⁿ⁺ ions from the plasma of a vacuum spark with a voltage up to 2.5 kV and a current rise rate up to 2 × 10¹⁰ A/s are studied using the time-of-flight method. At the initial stage of the discharge, bursts of beams of accelerated multiply charged ions from the cathode flame have been detected. It is established that the charge state distribution and energy of a beam are controlled by the initial voltage U ₀ of the capacitor. Upon an increase in this voltage, the average charge of copper ions attains the value +9, and the average charge of tantalum ions can be as high as +20, while the energy attains values of 150 and 350 keV, respectively. It is found that the average energy of ions with charge Z increases in proportion to the charge and is close to the energy eZU ₀ which would have been acquired by ions accelerated in the electric field of the discharge gap.