NUMERICAL METHOD FOR THE CALCULATION OF ELECTROMAGNETIC FIELDS IN QUASI-STATIC EMP PHASE OF THE CONTACT NUCLEAR EXPLOSION

A. I. Golubev, N. A. Ismailova
VANT. Ser.: Mat. Mod. Fiz. Proc. 1995. Вып.3. С. 3-8.

      A numerical method is described for the evaluation of electromagnetic fields in quasistatic evolution phase of EMP generated big contact nuclear explosion. The evaluation of fields in this phase reduces to the solution of Poisson equation for the potential of the electric field on the infinite domain containing air-soil interface.
      A new boundary condition is proposed for the potential of the soil computational boundary allowing to minimize the domain size.
      The Poisson equation is solved with the finite difference method. The potential grid values are calculated with the iterative method of variable directions using the “pre-alignment” of the difference equation coefficients. The way is shown how to choose the iterative parameter allowing to optimize the number of iterations required to achieve the desired accuracy.

      The problem setup is presented for the magnetic field flow in the cavity resulting from the expansion of the ionized cloud into homogeneous magnetized plasma. The problem includes both magnetic field diffusion to plasma due to collisions and plasma turbulence and magnetic field transport by Hollow currents.
      The dispersion properties of equations are discussed. The numerical algorithm is given for this problem. The discussion is presented for the restrictions of the timestop occuring if the electrons are highly magnetized from the conditions of difference scheme stability and iteration convergence when solving nonlinear difference equations.