## 6 Numerical Calculation Results
In zone II, filled with dielectric plasma, the direction of the current density vector \(\overrightarrow{j}\) is characterized by the presence of two radial \(j_{r}\) and axial \(j_{z}\) components approximately equivalent in magnitude, the interaction of which with the azimuthal magnetic field \(H_{\varphi}(r,\ \mathrm{\,z})\) provides continuous electromagnetic plasma acceleration both in the axial and radial directions up to velocities equal to the local values of the Alfven velocities \(V_{A}\), upon reaching which, magneto-gasdynamic discontinuities A\(\Phi\) and \(\Phi\)B are formed. The calculated position of these discontinuities, which are the boundary of region II of the effective pondermotor acceleration of the dielectric plasma at time -15 \(\mathrm{\,\,\upmu s}\), is illustrated by the spatial distributions of the Alfven velocity (Figure 3a) and the modulus of the plasma flow velocity (Figure 3b). A distinctive (from the explosive mode) feature of \(V_{A}\)\(\approx(p_{M}/p)^{1/2}\) behavior is its monotonic SW increase with distance from the surface of the electrode system and the achievement of maximum values at the point \(\Phi\) of intersection of shock-wave discontinuities (lines A\(\Phi\) and B\(\Phi\), Figure 2a). A characteristic feature of the transient regime is the relative smallness \(V_{A}\) in zones I (in the \(z>z_{\Phi}\)) and III, which indicates that the movement of plasma flows in these areas occurs mainly under the action of gasdynamic forces. The absolute velocity of dielectric plasma in zone II increases, approaching the boundaries of the discontinuities (lines A\(\Phi\) and \(\Phi\)B, Figure 2a), reaching the maximum values 30 km/s at the point of their intersection (\(\Phi\)). The characteristic level of the velocities achieved in this regime is much higher than the values of the plasma flow velocities in the Ohmic regime. The plasma density in zone II decreases monotonically with distance from the IDI surface, changing along the A\(\Phi\) discontinuity from values \(\rho\approx 0.03\)\(\mathrm{\,\,kg/m^{3}}\) (in the area of point A) to a value of \(\rho\approx 0.01\)\(\mathrm{\,\,kg/m^{3}}\) in the area of point \(\Phi\). An increase in the modulus of the dielectric plasma velocity along the discontinuities (lines A\(\Phi\) and \(\Phi\)B, Figure 2a) indicates an increase in the intensity of these discontinuities when approaching the point \(\Phi\). The appearance of significant values of the radial components of the plasma flow velocity IDI (10-30 \(\mathrm{\,km/s}\)) in zone II before the A\(\Phi\) discontinuity and its interaction with the dense paraxial plasma of metal vapors leads to shock-wave deceleration and, accordingly, the formation of a shock-compressed and heated region of dielectric plasma (zone Ib), which is the peripheral part of the cumulation zone I. The intensity of the strong magneto-gasdynamic SW, which is the outer boundary of this region, increases with distance from the surface of the MPC end, reaching a maximum in the region of the point \(\Phi\). However, despite an increase in the intensity of the rupture (A\(\Phi\) line, Figure 2a), the density of the shock-compressed dielectric plasma in the cumulation zone \(\rho_{\rm c}\approx\rho_{\rm p0}(\gamma+1)/(\gamma-1)\) decreases with increasing \(z\) due to a decrease in the incident flow density \(\rho_{\rm p0}\). Here, it is important to pay attention to the fact that the temperature of the shock-compressed plasma immediately behind the discontinuity along the A\(\Phi\) shock wave is practically constant and reaches values of 50-60 kK. This is because the plasma near the surface of the central electrode, where the current density is maximum flowing through it, is subject to maximum Joule heating, while the plasma temperature in the cumulation zone in the region of the \(\Phi\) point is determined only by the effect of plasma dynamic heating on SW.