METHOD AND DEVICE FOR PRODUCING MICROPARTICLE FLUX Russian patent published in 2003 - IPC

FIELD: plasma physics; research and engineering simulation of microparticle fluxes in space engineering. SUBSTANCE: proposed method and device are used for example to simulate impact of micrometeorite fluxes and finely dispersed particles of man-made origin polluting space at low-altitude nearearth orbits onto surfaces of optical and structural materials of space instrumentation. Method for producing microparticle fluxes at high-temperature erosion of plasma-forming material in vacuum in pulsed orifice flow discharge involves generation of plasma jet flow in magnetogasdynamic mode within electrode gap on condition that j_0MCD<j_0dis, where j_0MCD is current density in orifice plate corresponding to transfer of plasma jet flow to magnetogasdynamic mode [A/sq.cm; j₀ = i/πr²[A/sq.cm], where i is discharge current, A; r₀ is orifice plate diameter, cm; j_0dis is current density in orifice corresponding to ultimate strength σ_dis of orifice plate material, A/sq. cm); microparticles of total mass m_Σ are obtained provided Δh₀≥ΔH^*,, where Δh₀ is specific enthalpy at orifice axis, J/g; ΔH^* is specific destruction heat (ablation) of orifice plate material, J/g; m_Σ is found from expression m_Σ ≈ ωt_pulse[r], where ω is mean speed of orifice plate material carryover, g/s; t_pulse is discharge current pulse length, s; at microparticle speed of V_part(r_part) downstream of annular electrode found from expression , where C_x is coefficient including particle shape; V_jet is plasma jet speed at annular electrode, m/s; t_int is time of particle interaction with plasma jet in magnetogasdynamic mode of discharge, s; ρ_jet is plasma flow density, g/cu. cm; ρ_part is plasma density, g/ cu. cm; r_part is microparticle size, m. Microparticles of different chemical composition measuring between 0.1 and 900 mcm are produced in the process. Device for producing microparticle flux has pressurized discharge chamber incorporating power supply, gasvacuum system, annular electrodes carrying on their ends annular electrodes, 2l₀ thick, made of plasma-forming material with their hole, 2r₀ in diameter. Power supply is pulse-current generator operating in MGD mode of jet orifice discharge with i(t) value meeting condition P_magn>P_cr, where P_magn = (80π)^-1(0,2i/r₀)² is pressure due to discharge current magnetic field, Pa; is gas pressure in critical section, Pa; orifice plate is made of plasma-forming material. EFFECT: enhanced stability of high-speed microparticle generation. 7 cl, 2 dwg