Simulation of plasma behavior for medium propellant mass and pulsed energy of small scale pulsed inductive thruster

摘要

The pulsed inductive thruster is characterized of no electrode corruption and wide propellant choice.To give insight into the propulsion mechanism of small scale thruster at different propellant mass(m)and energy(E)levels,the transient Magneto Hydro Dynamics(MHD)method,completed by high temperature thermodynamic and transport,and plasma electrical models,is developed to study argon plasma response under the excitation of current of high rise rate.By calculating the two-dimensional expansion properties of the thruster with conical pylon,the simulations find that the main energy deposition occurs during the initial pulse rise stage,and the energy density of Joule heat is two magnitudes higher than the deposition in the down side.At propellant mass of 2 mg,average axial velocity of the current sheet increases from about 15 km/s at 750 J to about 21 km/s at 1470 J within the decoupling distance.The velocity variation synchronizes with the pulsed rise in the initial.The monotonically decrease of the temperature along axis results in the growth of low ionization level ions and reducing of high levels.The current sheet maintains the structure formed during the initial pulse rise when moving beyond the decoupling distance.Besides the change in forward velocity,the main difference is the dimension compared with that in the first half period,caused by thermal conduction and particle diffusion.The variations of total impulse It in the range of m from 2 mg to8 mg and E from 750 J to 1470 J show that It is proportional to m1/2 when E is determined.