Difference between a tokamak and a spherical tokamak

[chandrahas]

The title question is quite self-explanatory. Despite the fact that Spherical tokamaks are more spherical in shape, what else differentiates the ST from the conventional tokamak. I've heard that ST's use reverse field configurations from a website but I am skeptical about this since the rest suggest otherwise. Do ST' use reverse field configurations? And any other differences?

Thanks

 

[Dennis Jasbey]

The only difference is “aspect ratio”, the ratio of major radius to minor radio of the tokamak plasma. As the aspect ratio decreases, the plasma shape becomes less doughnut-like and more spherical-like, especially when the plasma has vertical elongation. When the aspect ratio is about 2.0 or below, the tokamak is arbitrarily called a “spherical torus” or "spherical tokamak."

There is NO reverse field or any other non-tokamak feature.

 

[chandrahas]

Oh. I think the reverse field thing is a part of the spheromak not the spherical tokamak . Got it. Thanks