About the aruora

New here. My English is not good.
I have a question.
How to make an aurora
like this
Shader - Shadertoy BETA come form shadertoy
In my past experience I will choose mesh . but in the sky? that`s crazy
so do you have other ideas?

That’s a tough one. Maybe look into raymarching? Ryan Brucks does interesting stuff with it: https://www.youtube.com/channel/UCSfF-j30GgtB_CpURE2v2jA/videos and Work.
If you can afford it, maybe using a technique similar to the fur shells one could work: https://twitter.com/radiatoryang/status/951175701704642560

Also : https://www.youtube.com/watch?v=5NzJhWTPxPw