## 4 Conclusions  
Different from the empirical formula for obtaining corona-generated audible noise based on experimental methods, this article starts from the generation process of a corona, adopts shock wave theory to simulate the explosive shock process of plasma based on the characteristics of the plasma, and establishes an acoustic wave propagation model considering actual situations. The electrosound-combined model proposed in this paper further reveals the generating mechanism of the acoustic wave of the corona. On the whole,  
Figure 16: The variation of sound pressure at different monitoring points: (**a**) Sound pressure; (**b**) Peak sound pressure.  
Figure 17: Comparison of the simulation and the measurement results of the time\(-\)domain waveform of the sound pressure.  
the study of our work provides a new approach and idea for simulating the audible noise generated by corona discharge. The main conclusions are as follows:  
* The plasma generated by the corona is mainly distributed near the axis of the corona field, where its electric field changes violently. During the formation of the plasma channel, a large amount of positive and negative ions is accumulated inside the channel, and the space charges counteract each other; thus, the overall performance is neutral, and the electric field inside the channel is very small. The continuous ionization in front of the plasma causes the accumulation of positive ions, and the electric field in front of it reaches its maximum value;
* The shock wave generated by plasma explosion propagates outward from the explosion point in the form of an arc, and there are obvious positive and negative pressure zones. The negative pressure zone is generated by excessive expansion caused by the inertia action of the shock wave, and its action time is longer than that of the positive zone. The propagation velocity decays extremely fast near the explosion point; then, it slowly decreases and decays to sound velocity at 10 cm;
* After attenuation, the shock wave pressure of the wavefront can be approximately equivalent to the sound pressure waveform. The sound wave expands outward in the form of a spherical wave, and it will be reflected when it propagates to the concrete surface. The positive peak value of the sound pressure pulse is always greater than negative, and the absolute ratio of them is between 1.3 and 1.6. After the sound pressure transforms from the expansion state of the positive half-wave to the compression state, it is affected by the viscosity of the air, and the negative half-peak value is smaller.  
The research on corona-generated audible noise in this paper mainly adopts a numerical simulation method, lacking more specific experimental evidence. Further work can be carried out on the construction of a pin-plate corona discharge test platform, the use of high-resolution optical and electrical measurement devices, and the installation of audible noise measurement systems. Some simulation parameters can be adjusted based on measurement results to make the simulation more accurate and reliable.  
Conceptualization, L.L. and F.Y.; methodology, L.L. and F.Y.; software, L.L. and P.W.; validation, F.Y.; formal analysis, P.W.; investigation, Z.L.; resources, Z.L.; data curation, P.W. and Z.L.; writing--original draft preparation, L.L.; writing--review and editing, L.L. and F.Y.; visualization, L.L. and Z.L.; supervision, F.Y. and P.W.; project administration, P.W.; funding acquisition, Z.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the China Southern Power Grid Technology Project (Grant No. 090000 KKS2220019).  
Not applicable.  
The authors declare no conflict of interest.