[JumpCrisscross]

> Are they trying to model every single atom?

Given all nuclear physics happens inside atoms, I'd hope they're being more precise.

Note that a frontier of fusion physics is characterising plasma flows. So even at the atom-by-atom level, we're nowhere close to a solved problem.

[amelius]

Or maybe it suffices to model the whole thing as a gas. It all depends on what they're trying to compute.

[JumpCrisscross]

> maybe it suffices to model the whole thing as a gas

What are you basing this on? Plasmas don't flow like gases even absent a magnetic field. They're self interacting, even in supersonic modes. This is like saying you can just model gases like liquids when trying to describe a plane--they're different states of matter.