A distribution of the magnetic field produced by permanent magnets in the DNBion source is calculated and analyzed in order to understand the plasma confinement in a cuspedmagnetic field and optimize plasma discharge.A uniform plasma is obtained in the experiment.
A control model of gas supply system is introduced for ion source and an adaptivediscrete-time control algorithm to regulate the hydrogen injection.A real-time feedback controlsystem(RFCS)is designed to control the gas supply for ion source based on the control modeland the discrete-time control algorithm.The experimental results have proved that RFCS couldregulate the gas supply smoothly,suppress the arc's abrupt over-current at the end of the ionsource discharging,prolong the discharge pulse and stabilize the ion concentration.With RFCS,the ion source for neutral beam injection has reached its longest pulse with a length of 4.5 secondsin a stable status.
Excellent vacuum performance ensures a high beam transmission efficiency of theneutral beam injector (NBI).The vacuum performance is mainly determined by the cryoperfor-mance of the cryopanel of the cryocondensation pumps which are the main vacuum pumps of NBI.In order to optimize the cryoperformance,the requirements for the temperature distribution andthe heat load of tire cryopanel are analysed and the factors that affect the cryopanel's temperaturedistribution are studied.The results indicate that.tire temperature difference of the cryopanel canbe reduced by fabricating the eryopanel with high thermal conductivity material,increasing itsthickness and cutting the distance between the two upward cooling pipes.The results may beapplied to a cryopanel cooled by forced flow liquid helium.
