Simulation Of Plasma Detachment Using Full-PIC Method

A magnetic nozzle converts a thermal energy of a plasma to a kinetic energy.That is one of future space propulsion systems.In addition,the magnetic nozzle can become an advanced thruster that has both advantages of large thrust and low fuel consumption rate when it operates a high energy plasma such as a nuclear fusion plasma.Although the magnetic nozzle obtains thrust from converting plasma momentums by Lorentz force generated between the magnetic field and an induced current in the plasma,it may not gain thrust when the ejected plasma attach to a magnetic flux line.In this research,a numerical analysis was conducted to clarify the condition of the plasma.We assumed a fully ionized plasma for simplification of a numerical modeling.We also needed a plasma simulation to solve a behavior of a plasma including kinetic effects of charged particles such as the cyclotron motion.Therefore,we applied a first principles calculation due to simulate the high temperature and low density plasma.The mean collision period of the plasma is long compared to the calculation period,so we ignored the effect of collision.A FullParticle-In-Cell(PIC)method simulates the motion of charged particles in a plasma: ions and electrons,and the equation of motion solve these.Also this method handles field values on grid points: magnetic field,electric field,and plasma current.the Maxwell's equations are solved through FDTD method.The problem is a high calculation cost of particle calculation.Therefore,we used a parallel calculation method and confirmed the effect.We analyzed plasma flow across the magnetic field and the cyclotron radius of ion and electron statistically.Finally,we discussed about an evaluation method of electron detachment to use the relationship between the cyclotron radius and the magnetic scale length: B/|(?)B|.