Investigation of the poloidal magnetic flux at the PF-3 plasma focus within the framework of the program of laboratory simulation of astrophysical jets

Abstract

Astrophysical jets are collimated plasma outflows observed in diverse astrophysical settings covering seven decades of spatial scale and twenty decades of power, which, nevertheless, share many common features. This similarity over wide range of scales indicates a common core of physics underlying this phenomenon, leading to considerable interest in observational, theoretical and numerical studies. Laboratory astrophysics experiments for simulating astrophysical jets are premised on this common core of physics responsible for multi-scale similarity of jets remaining valid down to laboratory spatial scales of millimeters. Jets formed after the disassembly of the non-cylindrical z-pinch formed in a plasma focus installation have recently been subjects of observational studies. They offer an important complementarity to the main lines of investigations in two respects. Firstly, the multi-faceted role of gravity, radiation, nuclear reactions and related astrophysics is eliminated retaining only a rapid implosion of a compact plasma object in a magnetohydrodynamic environment as a common feature. Secondly, observations can be made using techniques of laboratory plasma diagnostics. In this paper, we report preliminary results regarding presence of poloidal magnetic flux associated with the jets lasting long after the pinch disassembly. This is significant in the context of uncertainty regarding the origin of poloidal magnetic field postulated in several MHD models of astrophysical jet phenomena. Evidence indicating presence of a radial component of electric field suggests existence of plasma rotation as well. These results suggest that more refined experiments can provide insights into the astrophysical jetting phenomena not available from observational astronomy techniques.