Speaker
Description
The gas pressure during plasma discharge affects the density and temperature of its electrons, which is essential to realize the steady-state operation of the radio frequency negative hydrogen ion source used in the nuclear fusion auxiliary heating experimental device.In order to maintain the density and uniformity of the plasma and improve the operating efficiency of the ion source.It is necessary to keep the gas pressure during plasma excitation of the ion source and the gas pressure during beam extraction within a certain range.By simulating the dynamic changes of vacuum in the ion source with different gas flow rates, gas intake times and pumping speeds, hardware circuits are designed to control solenoid valves and mass flow controllers (MFC) to achieve the precise control of gas flow.The experimental results in the RF test facility of ASIPP NBI show that the precisely controlled gas flow strategy designed has better repeatability and more stable density and uniformity of the plasma .At the same time, gas flow is also an important reference for the calculation of the real-time pumping speed performance of cryopumps and the analysis of the reasons for the failure of the beam extraction experiment.
