## 6 Numerical Calculation Results
In this case, the radial expansion of the metal plasma jet is restrained by the action of the forces of the dynamic pressure converging to the axis of the dielectric plasma flow and magnetic pressure. As a result, a narrow (with a radius smaller than the cathode radius) jet is formed, the axial continuous acceleration of which to supersonic speeds is carried out mainly by gasdynamic forces. The flow is accelerated up to the sonic velocity near the electrode on a narrowing section under the conditions of Joule heat release up to supersonic speeds--in the expansion zone under conditions of heat release by radiation and interaction with a high-speed dielectric plasma flow. Shockless acceleration of the axial jet of metal plasma occurs up to contact with the shock-compressed plasma region in the axial part of the outer boundary of the discharge. By the moment of time 0.3-0.4 \(t_{1}\), the area of cumulation I takes the form shown in Figure 2a and consists of the axial zone Ia of the metal vapor plasma of the central electrode and the surrounding zone Ib of the dielectric vapor plasma. Typical for a given transient regime, the distribution patterns in space of the main thermal gasdynamic parameters at the time 15.3 \(\upmu\)s of the maximum discharge current (285 kA) for an MPC discharge in Ar with an initial pressure 0.1 atm at \(C=750\ \upmu\)F and \(U_{0}=5\ \mathrm{\,kV}\) (\(A_{m}=0.6\)) are shown in Figures 2 and 3. The outer boundary of the discharge is a strong gasdynamic SW. At the speed of movement of the GSW axial part \(D\approx 6.5\ \mathrm{km/s}\), the density ratio \(\rho_{\rm SW}/\rho_{0}\approx 8\) reachesits limiting gasdynamic value. The value of the axial coordinate \(z_{m}\) of the position of the bow shock wave at the time of the current maximum reaches values \(z_{m}\approx 85\)\(\mathrm{\,\,mm}\). The radial expansion of SW along the surface of the electrode system is much lower (\(D_{r}\approx 1.5\)\(\mathrm{\,km/s}\), \(\rho_{\mathrm{SW}}/\rho_{0}\approx 3\)). With a general conical shape of the SW, characteristic (for modes with manifestation of plasma dynamic effects) kinks of the GSW front are observed at the point with coordinates \(r\approx 36\)\(\mathrm{\,\,mm}\), \(\mathrm{\,z}\approx 36\)\(\mathrm{\,\,mm}\) (at a given time), arising from the intersection of GSW with different intensities. Radiation-magneto plasma dynamics processes occurring with the light erosion plasma of dielectric vapors in zone II determine the further dynamics of plasma formation, its structure, and parameters. The near-surface plasma of a dielectric is accelerated by electromagnetic forces in the \(z\)-th direction up to velocities of 5 \(\div\) 10 \(\mathrm{\,km/s}\) in a narrow (0.5 \(\mathrm{\,cm}\)), radially limited (\(r\leq 3\)\(\mathrm{\,cm}\)) layer. In the IDI zone, adjacent to the outer surface of the central electrode, the flowing currents have commensurate components \(j_{z}\approx j_{r}\), which lead to the appearance of the movement of the dielectric plasma in the radial direction (to the axis of the system) in the region of point A. The pattern of the further movement of the formed flows of the erosional plasma of the dielectric is determined by the space-time distribution of the current density. Calculations have shown that, for transient regimes with \(A_{m}\)-0.4-0.8, the region of current flow is limited by zone II and the initial (\(0<z<z_{\Phi}\)) cumulation region. At the same time, in the axial region, the current density has mainly only the \(j_{z}\)-th component, the value of which monotonically decreases with distance from the MPC end face, and at \(z\approx z_{\Phi}\), \(j_{z}\approx 0\).