Abstract: A model of the hybrid cathode attachment of a high-current vacuum arc with a characteristic average current density at the cathode of 105–106 A/cm2, in which multiple rapidly moving cathode spots and a quasi-stationary thermal spot coexist, is proposed. The numerical simulation of the formation and expansion of a plasma jet with a hybrid cathode attachment showed that the model can explain the sharp increase in the mass of the plasma jet and cathode erosion observed in experiments on magnetic implosion. Characteristic signs of the occurrence of hybrid cathode attachment, which can be verified experimentally, are predicted. © Pleiades Publishing, Ltd. 2023. ISSN 1062-8738, Bulletin of the Russian Academy of Sciences: Physics, 2023, Vol. 87, Suppl. 2, pp. S169–S174. Pleiades Publishing, Ltd., 2023.