Arc in a Gas Flowing Through a Magnetic Field

The authors have previously shown that ad.c. electric arc can be used in the pre-ionizer of a non-equilibrium MHD generator. The pre-ionizer must be located immediately before the duct inlet, where the magnetic field is fairly strong and may have a substantial effect on the current in the gas flow. In the present paper they consider the behaviour of an electric arc in a gas flowing through a magnetic field. The experiments were carried out with argon, using the apparatus described in Ref. [1] of the paper. The flow was set up in a closed glass loop by means of an electromagnetic accelerator (MHD motor). By suitably treating and adjusting the loop it was possible to conduct the investigations in spectrally pure argon. The pressure varied between 1 and 100 mm Hg, and the flow velocity V0≤ 104 cm/sec. The magnetic field in the accelerator (B1) and near the arc (B2) varied between zero and 7 x 103 Oe. The spatial distribution of the electron concentration (ne) and the electron temperature (Te) were measured using probe and spectrum analysis methods. The gas temperature (Tg ) was measured by the hot wire method and the flow velocity with the help of pitot tubes. Experiments were carried out in both decelerating and accelerating magnetic fields. (author)