Studying the Van Allen Radiation Belts

Sometimes on TV documentaries when talking about the discovery of Van Allen belts, they show this 1950s footage of a particular experiment in which a small globe is set in place at some sort of paritcle stream is shot at it. This then produces a Van Allen belt effect around the globe.

Can anyone illudicate on what this experiment may be? I’m assuming the globe has a strong bar magnet inside and the whole thing is in an evacuated chamber; electrons are then shot at the globe.

As a guess, it may be an example of a terrella. (There’s a better copy of the photograph on this page.)

Yep, that looks just like it.