Abstract:
In this article the evolution of laser plasma in an external magnetic field of a various initial configuration is investigated. The equations of ideal magnetohydrodynamics in cylindrical system of coordinates by means of conservative TVD different scheme of the second order on space and time have been solved numerically. In the initial moment of time heating of the target consisting of plasma of steams of aluminium was carried out by action of a short laser impulse by duration of $30$ nanoseconds and Gaussian profile on space with a half-width $0.03$ cm. The cases of poloidal and a toroidal magnetic field are considered at various values of plasma parameter. Results of numerical calculation with poloidal magnetic field show that plasma not so strongly pressed to an axis and is engaged much more volume in computing area at comparison with a case of a homogeneous vertical magnetic field. Density jump at the front a shock wave is more extended and is formed further from axis $OZ$. In a strong toroidal magnetic field practically there is no radial expansion of plasma, the substance moves only along a vertical direction under the influence of Lorentz's force. The forward front of a laser plume is narrow, one moves ahead on more long distance along axis $OZ$ and it has the high kinetic energy, than in case of weaker toroidal field.