激光等离子体实验中脉冲强磁场设备产生的电磁干扰和屏蔽方法

Pulsed intense magnetic fields play an important role in the field of high power laser material interaction, while the electromagnetic pulse generated by pulsed intense magnetic field devices will disturb the signal measurement in laser plasma experiment. We measured the spatial distribution and spectral characteristics of electromagnetic pulse using Rogowski coils, high-voltage probes, antennas, and sampling resistors on the laser plasma experimental platform. It is found that the electromagnetic pulses come from the main discharge circuit of the pulsed intense magnetic field device, and the secondary circuit of charging and grounding. The electromagnetic pulses transform onto the vacuum target chamber through capacitive coupling between the transmission line and the flange on the vacuum target chamber that places the transmission line, and then enter the electronic devices through conductive coupling pathways, or enter the power grid or weak current cables through charging lines and grounding wires, and finally enter the electronic devices. Part of the free space electromagnetic pulse is directly coupled into cables and electronic devices. We depress the electromagnetic noise that enters the detector by disconnecting the conductive coupling path and shielding free space electromagnetic pulse. Experiments showed that the measured electromagnetic pulse amplitude, especially at the 0.14 MHz discharge main frequency component, was well suppressed, by physically disconnecting the electrical connection between the power grid and electronic equipment. Isolating the high-voltage power supply from the low-voltage grounding connection can decrease the electromagnetic noise markedly. Shielding shell and shielding cabinet that cover the electronic devices are available approaches to depress the free space and conductive coupled electromagnetic noise.