Energy transportation via MITL by the linear current flow density up to 7 MA/cm

Abstract

The transmission properties of the magnetically self-insulated vacuum transporting line (MITL) were studied on the S-300 pulsed power machine (3 MA, 100 ns) at the high linear current flow density up to dI/db = 7 MA/cm. Experiments were carried out with the short line sections with 10 ÷ 15 mm length and 3 ÷ 5 mm vacuum gap. For measuring of the plasma parameters, the frame ICT photography with the nanosecond temporal resolution in the SXR range and ICT (Image Converter Tube) chronography in visible range were used. The X-ray radiation in various ranges was recorded by the XRD with thin filters (SXR) and by the semiconductor detectors (HXR). The information about current transmission efficiency was obtained by means of magnetic loops and low-inductance shunt. It was determined that dense plasma arose on both anode and cathode when the linear current flow density was low enough, dI/db ≤ 1 MA/cm. A dense plasma moves across the vacuum gap with the velocity (1 ÷ 2) × 106 cm/s. By recording the current and hard X-ray radiation it was found that electron losses in the current front did not exceed 10 ÷ 100 kA. Under strong magnetization of electrons rH = mvc/eB < d, these losses could be due to the motion of fast plasma component, which velocity exceeds 107 cm/s. Such a rare plasma sheath formed on the cathode by dI/db ≥ 1 MA/cm. Thereby the successful physical modeling of the recyclable MITL related to the Sandia Laboratories’ Conceptual Project of fusion reactor on the base of fast Z-pinch has been brought about.