V.M. Astashynski

Electric and thermodynamic properties of plasma flows created by a magnetoplasma compressor

A magnetoplasma compressor of compact geometry (MPC-CG) with a semi-transparent electrode system that operates in the ion current transfer regime was constructed and studied. The electric and thermodynamic parameters of the discharge and the plasma flow created in different gases and their mixtures (hydrogen, nitrogen, argon and Ar + 3% H2) have been measured to optimize the working conditions within the 100–3000 Pa pressure range for input energy up to 6.4 kJ. A special construction of the accelerator electrode system shielded by the self-magnetic field results in protection from erosion, which is the main cause of the high current cut-off in conventional plasma accelerators. It was found that the compression plasma flow velocity, electron density and temperature predominantly depend on the energy conversion rate from the energy supply to the plasma, since the current cut-off is avoided. The maximum energy conversion rate for MPC-CG was found when operating in hydrogen. The plasma flow velocity and electron density maximum values are measured close to 100 km s−1 and 1017 cm−3, respectively, for input energy of 6.4 kJ at 1000 Pa pressure in hydrogen. Our results appear in good agreement with existing theoretical and experimental data.

Compressive plasma flows interaction with steel surface: structure and mechanical properties of modified layer

The interaction of a dense compressive nitrogen plasma flow with carbon steel specimens has been investigated. The flows were generated by a magnetoplasma compressor, in which the acceleration of a plasma is accompanied by its compression due to interaction between the longitudinal constituent of electric current and the intrinsic azimuth magnetic field. As a result, a layered structure with a total depth of up to 25 μm is formed at a specimen surface. Investigations of a surface structure and its phase composition were carried out using X-ray diffraction, Mossbauer conversion electronic spectroscopy, and optical microscopy methods, along with the studies of mechanical properties.

Modification of Solid Surface by a Compression Plasma Flow

The main characteristics of several types of quasi-stationary plasma accelerators applicable in solid surface modifications have been described. The emphasis is on their applications in (i) obtaining the materials with improved qualities, (ii) creation of sub-micron highly oriented structures on silicon single crystal due to compression plasma flow action. The influence of external magnetic field on dimensions of created structures has been also observed and discussed