Plasma diamagnetic effect in multipole galatea trap

Precise determination of plasma parameters is essential for multipole Galatea magnetic trap experiments. We put forward an experimental method especially based on the diamagnetic diagnosis.The simulation model of multipole Galatea magnetic trap was established and the characteristics of diamagnetic current and pressure distribution in the magnetic trap were analyzed, then a mathematical model was presented combining with the diamagnetic current and plasma separating surface pressure. According to the ideal gas equation, a method of estimating energy confinement time and plasma temperature by using plasma diamagnetic current was also presented. According to the diamagnetic current measured by Rogowski coil and digital integrator and the proposed mathematical model, the dependences of the pressure on the plasma boundary surface, energy confinement time, and plasma temperature for different magnetic field barrier were obtained.The experimental results show that when the barrier magnetic field changes from 0.025 T to 0.1 T, plasma diamagnetic current will change from 60 A to 110 A, the plasma boundary pressure will change from 9 Pa to 14 Pa, plasma energy confinement time will change from 55 μs to 150 μs, and the temperature of the plasma is about 10 eV, which is basically identical with the measured results determined with the help of calorimeter. Calculation results show that under the condition that the plasma concentration values are known, energy confinement time and plasma temperature can be measured by diamagnetic current.