Significance of the solar wind

External Since: Aug 22, 2004 Posts: 78

In article <8b42afac.0409140704.38a79936.DeleteThis@posting.google.com>,
kuyper.DeleteThis@wizard.net (James Kuyper) wrote:

> steve.DeleteThis@antispam.sforbesa.cix.co.uk (Stephen Forbes) wrote in message
> news:<memo.20040913222747.20071G.DeleteThis@sforbesa.compulink.co.uk>...
  > > In article <8b42afac.0409130433.3abc7b17.DeleteThis@posting.google.com>,
  > > kuyper.DeleteThis@wizard.net (James Kuyper) wrote:
  > >
   > > > What was the exact text of the message he sent
   > > > you expressing his opinion that you were correct?
  > >
  > > Ok then.
  > >
   > > > Interesting.
   > > > The velocity of the top 1% of atmosphere will work its way down to
  > > the
   > > > surface, whether or not you've got that "cross wall" or bridge.
   > > > The long
   > > > term problems are:
   > > > Slowing of the Ringworld.
   > > > Increase in hydrogen. More oxygen tied up in water molecules. The
   > > > increase
   > > > might be balanced by air (especially hydrogen) escaping over the
   > > > rim walls.
   > > > Something would have to be done.
  > >
  > > He certainly didn't say anything like it couldn't happen, he's
  > > discussing the consequences of it happening.
>
> Every consequence he describes is one we've all agreed would happen.
> The question isn't about whether it happens, it's about whether it
> happens fast enought to matter. I can't tell from this clip whether or
> not he's bothered checking your calculations, so I can't tell whether
> he's even aware that the relevant time scales are measured in billions
> of years, rather than the 100 years that you have claimed. The Pak are

Assume I used legitimate numbers, because I did. I explained every step
and where every number came from. It was a longish email.
I know, you want to see it now, but its essentially the same as what I
posted here earlier so I won't regardless of any needling from you.

> fully capable of thinking and planning on long time scales, so
> "something would have to be done" could be consistent with the correct
> time scale, but I agree it's more consistent with Niven having
> incorrectly accepted the much shorter time scales that you've argued
> for.
>

Call me paranoid but:
If Larry agrees with you guys its 100% incontrovertible, regardless.
If Larry agrees with me it must be because he didn't understand that I'm
always wrong, regardless.

Here you are questioning Larry's words, not because they conflict with
what he published in his books, but because they conflict with your point
of view. I, at least, questioned what he said to JesusX because it was an
obvious conflict with "Engineers". Where's your justification?

BTW I came across this Nasa site. Enjoy your humble pie!
<a style='text-decoration: underline;' href="http://science.msfc.nasa.gov/ssl/pad/sppb/edu/magnetosphere/mag4.html" target="_blank">http://science.msfc.nasa.gov/ssl/pad/sppb/edu/magnetosphere/mag4.html</a>

Stephen

<a style='text-decoration: underline;' href="http://www.cix.co.uk/~sforbesa" target="_blank">http://www.cix.co.uk/~sforbesa</a>

External Since: Jul 14, 2004 Posts: 62

steve.TakeThisOut@antispam.sforbesa.cix.co.uk (Stephen Forbes) wrote in message news:<memo.20040914211657.19947C.TakeThisOut@sforbesa.compulink.co.uk>...
> In article <8b42afac.0409140657.42e87ca4.TakeThisOut@posting.google.com>,
> kuyper.TakeThisOut@wizard.net (James Kuyper) wrote:
....
  > > Call it obvious, if you wish, but I don't see any basis for those
  > > assertions. What would cause those burn marks? Charged plasma spirals
  > > around magnetic field lines. If you choose the intensity of the
  > > magnetic field properly, the radius of the spirals will be just large
  > > enough to divert the solar wind away from the Ringworld and into a
  > > region where the magnetic field is weak enough that the radius of the
  > > spiral increases to infinity, thereby releasing the charged particles.
>
> This actually has me confused. You want to form a uniform vertical
> magnetic field across the width of the Ringworld.

It can't be uniform because the Ringworld is a cylinder of finite
length. As a general rule, edge effects make it impossible for an
electromagnetic field to be exactly uniform. However, it doesn't have
to be perfectly uniform for this approach to succeed.

HOW??? Please answer
> this question. I cannot see the superconductor grid doing this, I can only
> see horizontal field lines above the grid and vertical lines in the middle
> of each hexagon. Are you only going to use 1 in every 7 hexagon because
> even that won't form a uniform field.

It's pretty simple. Choose the region within which you want to set up
a nearly uniform field with a primarily vertical orientation. Route
the electric current through the hexagaon grid on a path that follows
as closely as possible the perimeter of that region. The resulting
horizontal current loop necessarily produces a magnetic field that is
primarily vertical throughout the region inside the current loop, and
for a considerable distance above and below the current loop.

  > > Not when the main component of their velocity of the protons is
  > > anti-spinward, and the radius of the spiral is adjusted to be on the
  > > order of 1 million miles. Then the spiral will simply divert the flow
  > > either to port or starboard.
  > >
>
> What strength of field? This is your baby so its up to you to justify this
> with numbers and patterns. I can't see it working, please prove me wrong.

That's trivial enough - I assumed you were familiar with the formula.
In the appropriate units, it takes the form B=m*v*c/r*q, where 'm' is
the mass of the charged particle, v is the component of it's velocity
transverse to the the magnetic field, c is the speed of light, r is
the radius of the spiral, and q is the charge of the particle. I don't
see much point in plugging actual numbers into that equation; we've no
information about the limits on the superconductor being used, and
therefore no basis for saying that any particular magnetic field
strength is unattainable. I will point out that the radius of the
spirals in the Earth's magnetic field is immensely smaller than 1
million miles, and the required field strength is inversely
proportional to the spiral radius. As a result, the field required to
keep the Ringworld safe is much weaker than the one needed to keep the
Earth safe.

If it seems counter-intuitive that such a tiny field is sufficient,
keep in mind that the mechanism I describe requires that this very
weak magnetic field must remain at least moderately uniform over
millions of miles; the total energy of that volume of magnitic field
is enormous, despite the fact that the field itself is quite weak.

This isn't possible for the Earth's magnetic field. The current loops
that generate it are only a few hundred miles wide, at best, so the
magnetic field they generate drops off quite rapidly with distance.
The current loop I've described is a million miles wide, and millions
of miles long. The magnetic field it produces will therefore trivially
extend the million or so miles outward that it needs to extend, in
order for this mechanism to work.