The city was under siege, and Yan stood at the epicenter, electric arcs crackling around him.

城市被围困，严站震中，周围电弧噼啪作响。

During this process, an electric current passes through the gas, creating an electric arc, which moves in the direction of the gas stream while the arc length lengthens.

程中，电流通气体，产生电弧，电弧气流方向上移动，同时电弧长度也随之变长。