Re: [Phys-L] charge in an increasing magnetic field

[brian whatcott <betwys1@sbcglobal.net>]

The Betatron is alive and well and is used in quantity today for 
radiographically examining defects in a 12 inch thick steel section for 
example:

http://www.globalxray.com/industrial-radiography

It's important to remember that Betatrons use shaped pole pieces in 
order to obtain the
non-uniform (in space) magnetic field needed to hold a reasonably 
constant orbital radius over the (quarter) period of increasing field.

Brian Whatcott

On 4/17/2015 11:10 AM, John Denker wrote:
> It is not possible to create a magnetic field that is
> uniform across all of space. /snip/
>
> On 04/15/2015 09:23 AM, Philip Keller wrote:
>
> > A region of space is filled with a uniform magnetic field, directed in the
> > z-direction, increasing linearly with time, with the "center of the field
> > at the origin.
> /snip/
>
> People actually built and operated a number of betatrons
> in the 1940s and 50s, so it is entirely reasonable to
> ask about such things.
>
> __