摘要：We found an error in our previous report [Chin. Phys. Lett. 34 （2017） 012902] concerning about the value of voltage on the modulating anode （MA）. This mistake occurs when we shifted calculating positive scale to actual negative voltage scale in the DGUN simulation. The value of voltage on the MA is VMA = -33.5 kV as displayed in Table 1. Also Figs. 2（a）, 2（b） and 4（a） should be as follows. We note that the error does not affect the conclusion of our report at all, and we apologize for inconvenience of readers brought by our oversight.