[ExI] Physical limits of electromagnetic launchers

[Jeff Davis]

Friends,

I ran some numbers through the calculator.  Used one Kg in order to get a
unit centripetal force -- ie force per Kg,... used 0.1c for the velocity,
and 100,000,000 miles for the ring radius (rounded up the 93,000,000 mile
earth orbit radius) and got 57 times the force of 1kg at one gee.

For launching solid stuff, this a manageable problem right?.  Humans, using
a temporary liquid breathing medium (fluorocarbons) and immersed in liquid
might be able to tolerate this gee load.

If you make the radius 100 times larger, then the gee force goes down to
2.5.  Now I know a ring 100 AU in radius is big, but traveling to the stars
is a big project, no?

Regarding the Bremstrahlung/maglev heating problem, I can't comment, I'm
only very slightly acquainted with that physics.

Best, Jeff Davis

On Sun, Jun 3, 2012 at 8:47 AM, spike <spike66 at att.net> wrote:

> ** **
>
> >... On Behalf Of Anders Sandberg
> ...****
>
> ** **
>
> >…But maglev is electric charge, when you start looking at it
> relativistically! A pure magnetic field will look like it has electrical
> components when you move through it fast enough.  -- Anders Sandberg****
>
> ** **
>
> ** **
>
> ** **
>
> Understatement, Dr. Sandberg.  Any mothion at any speed through a magnetic
> field will induce an electric field, in accordance with Faraday’s notion of
> del cross E is the negative of partial derivative the magnetic field with
> respect to time:****
>
> ** **
>
> ****
>
> ** **
>
> Moving through a magnetic field is the same as a changing magnetic field
> from the point of view of the moving particle, which means maglev and any
> electromagnetic propulsion will result in heating.****
>
> ** **
>
> For a really interesting example of that, there is at Disneyland a roller
> coaster (California Screamin’) that is initially launched by maglev.  I
> stood watching that for a while.  Immediately after each launch a number of
> nozzles spray water on the track, which creates steam.  Kewallll…****
>
> ** **
>
> spike ****
>
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>
>
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