Transformation of axial magnetic field during neutron production on the MA plasma focus with deuterium filling

Abstract

Summary form only given. In this contribution we present the results of experimental studies of the pinch evolution on the PF-1000. The calibrated magnetic probes in different radial positions were correlated with neutron production and with interferometry images. The characteristics of probe measurement of azimutal magnetic field on the PF-1000 were published in [1]. The transformations of the pinched column during different types of neutron production on this device were published in [2]. In this presentation the new results are presented using measurement of axial (Bz) and azimutal (Bϕ) component of magnetic field. The current layer imploding the dense plasma sheath is 2–3 cm thick with dominant part of the current out of the dense plasma sheath. This layer is composed from Bϕ and Bz component, Bz component is roughly 4 – 6 times lower. After achieving the minimal diameter of the plasma column the current layer penetrates into the dense plasma and at the start of explosion the total current layer is absorbed in the dense column. The formation and evolution of m=0 instability correlates with axial fluctuation of Bz. The Bz in the imploding necks decreases and in the expanding dense disks and plasmoids between them increases. The values of Bz reached 1–2 T, about 20% of the Bϕ values on the dense plasma column boundary. During the first neutron pulse the Bz field in the axis increases and during the dominant neutron production the Bz decreases.