## 6 Numerical Calculation Results  
Calculations were carried out for MPC in argon and air in the range of pressure \(p_{0}=10^{3}\div 10^{5}\) Pa at temperature \(T_{0}=300\) K. Basic geometric dimensions of MPC: \(r_{1}=0.8\) cm, \(r_{2}=5\) cm, \(r_{3}=6\) cm. Separate calculations were performed for MPC discharges with a variation in \(r_{1}=0.4\)-\(1\) cm, \(r_{2}=2\)-\(5\) cm. PTFE-4 was selected as the IDI material. The electrodes were made of copper. The capacity of the power storage took the values \(C=28.6\)\(\mu\)F (with variation of the initial voltage \(U_{0}=10\div 200\) kV, \(W_{0}=1.43\)-\(570\) kJ) and \(C=750\)\(\mu\)F (\(U_{0}=2\div 20\) kV, \(W_{0}=1.5\)-\(150\) kJ). The value of the external active resistance of the discharge was \(R_{0}=10^{-4}\) Ohm, and the external inductance of the discharge circuit was \(L_{0}\approx 70\) nH. Let us introduce the value \(\lambda_{R}\) for the analysis of the obtained results:  
\[\lambda_{R}=R_{Olm}/R_{pl},\]  
where \(R_{Olm}\) is the Ohmic resistance of the MPC-discharge and \(R_{pl}\) is the plasma resistance. The value \(\lambda_{R}\) is proportional to the ratio of the Joule heating power to the total power supplied to the plasma load. It reflects the contribution of Ohmic and plasma dynamic mechanisms of plasma heating. In addition, we introduce a dimensionless criterion \(A_{m}\), which can be used to characterize the entire sum of modes in an MPC discharge. This dimensionless criterion is the ratio of the mean integral (along the midsection of the MPC) magnetic pressure \(\overline{p}_{m}(z=0,\ t_{m})\) to the total velocity head \(\rho_{0}D^{2}\) of the gas flow \"incident\" to SW. This parameter can be used to estimate the contribution of the plasma dynamic and Ohmic mechanisms of energy dissipation to the discharge plasma:  
\[A_{m}=\bigg{(}\frac{\overline{p}_{m}(z=0,\ t_{m})}{\rho_{0}D^{2}}\bigg{)}^{1/2}.\]  
In structure, this parameter is the square root of the Alfven number. Physically, it can be interpreted as the ratio of the pondermotor forces acting on the plasma, which characterize the work of electromagnetic forces (and, consequently, the role of the plasma dynamic mechanism of energy dissipation) to the characteristic value of all forces actually acting on the plasma, including gasdynamic forces (reflecting the influence of the Joule dissipation mechanism energy), causing the movement of the SW head in gas at an average speed \(D\). At values \(A_{m}\to 1\), the influence of pondermotor forces and the work performed by them becomes decisive both in power and in energy terms--the fraction of the Ohmic resistance of the plasma load should tend to the minimum value (\(\lambda_{R}\to\lambda_{\rm{Emin}}\)), and, therefore, the plasma dynamic mechanism of energy dissipation becomes the main one. At \(A_{m}\to 0\), on the contrary, the plasma is heated only as a result of Ohmic heating, and acceleration--under the action of gasdynamic forces. The calculations showed that, depending on the value \(A_{m}\), i.e., depending on the role of one or another heating mode (Ohmic, transient, and plasma dynamic), there are three different types of quasi-stationary spatial distributions of plasma parameters which can be used to judge the features of the emerging structures and the dynamics of plasma propagation, and, consequently, to discuss the modes of discharge. At \(A_{m}<0.4\), the Ohmic heating mode (\(\lambda_{R}\geq 0.8\)) is realized with an insignificant fraction of kinetic energy in the total plasma energy (\(\lambda_{\rm{E}}\leq 0.1\)). In the range \(A_{m}\approx 0.4\)-\(0.8\), a transitional mode (\(\lambda_{\rm{R}}\approx 0.4\)-\(0.8\)) is realized, in which the role of the Ohmic and plasma dynamic heating mechanisms are approximately the same. In what follows, we will consider only the features of radiation plasma dynamics (RPD) structures and the behavior of the main parameters of the MPC discharge plasma in the transition regime, which is most interesting from the physical point of view.