David Kirtley

In a magnetic system, your goal is not to push together those particles as fast as possible.

Your goal is to hold on to them for as long as possible.

And to do that, we use magnetic fields.

So let's take a step back.

What is a magnetic field?

So in an electromagnet, there's a variety of ways to make a magnetic field.

One of the most famous I think everyone is familiar with is Earth itself.

Earth has what we call the magnetosphere, which is the magnetic protection that's generated actually by the core of the Earth.

But we have a magnetic field around the Earth, and that magnetic field protects us from particles coming from the galaxy, galactic cosmic rays coming

And solar particles that would come to Earth, that magnetic field, when you run a compass, you see the magnetic field from the Earth.

So we know it's happening.

It's all over.

But how we generate it with electric currents is a little bit different.

And what we do is that we have a loop of wire.

And the simplest way to think about it is literally a round loop.

And in that loop, you have electrons.

You have an electrical current that's running.

And when electrical current, this is some of Maxwell's equations that we discovered in the 1800s, that when you have an electrical current and a wire, it generates a magnetic field inside that wire.

And so when you look at fusion systems, you always have these big magnetic coils with large amounts of current.

We don't run a little bit of current.