The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN d...The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered. The voltage waveform varies periodically due to the motion of the filament. The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates. Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction, it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.展开更多
A magnetic measurement system consisting of magnetic probes and flux loops for spherical tokamak SUNIST, is uniquely designed due to the strongly shaped plasma cross section and the narrow space near the central solen...A magnetic measurement system consisting of magnetic probes and flux loops for spherical tokamak SUNIST, is uniquely designed due to the strongly shaped plasma cross section and the narrow space near the central solenoid. Plasma equilibrium reconstruction with the current filament method is performed to determine the number and positions of the magnetic probes and flux loops, as well as their design precision required.展开更多
基金Project supported by the National Natural Science Foundation of China(No.60776034)
文摘The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered. The voltage waveform varies periodically due to the motion of the filament. The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates. Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction, it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.
基金National Science Foundation of China(No.10535020)the Foundation for the Authors of National Excellent Doctoral Dissertation of China(No.200456)
文摘A magnetic measurement system consisting of magnetic probes and flux loops for spherical tokamak SUNIST, is uniquely designed due to the strongly shaped plasma cross section and the narrow space near the central solenoid. Plasma equilibrium reconstruction with the current filament method is performed to determine the number and positions of the magnetic probes and flux loops, as well as their design precision required.
