Gotta say I don’t have a great solution for you if it needs to animate.
I made this with a mesh, but it uses the camera vector for falloff, so it is rather view dependent. A custom raymarcher would work, but it is by far the most complicated to set up as it requires a loop so it has to be done in a custom node in HLSL. If you want to go that route my advice would be Inigo Quilez articles and Ryan Brucks blog posts on the topic.