所谓突然一阵灵感 a flash of inspiration 就是说一个人头脑里突然冒出一个创新或革新的想法或闪念。

例句

John's new travel book was a huge success after the flash of inspiration he got while sitting on the bus.

The idea for my song came to me in a flash of inspiration!

请注意

另一个短语 a flash in the pan 意思是昙花一现，指短时间的走红或暴热。

例句

Susan had a number one hit with her song, but after that we never heard from her again. People said she was just a flash in the pan.