Re: GEO debris (was: Re: Useless hypotheses)

From: Spike Jones (
Date: Sat Dec 22 2001 - 18:37:31 MST

Amara Graps wrote:

> How would you define sub-orbital ... ? (LEO?)

I meant sub-LEO. The particles have insufficient velocity to
make LEO, since they are fired backwards from a motor
that itself is at suborbital speed. Then the charged exhaust
particles pick up velocity from interaction with charged particles
from the sun. Then the exhaust particles go neutral by
interaction with ions in earth orbit, so that the solar wind is not
able to push them right out of orbit.

> > Then the charged particle would interact with the solar wind,
> solar wind where? which side of the magnetosphere? at 10 R_Earth ..?

Uh oh, I am way outta my expertise here. Do let me study up on
the configuration of the magnetosphere, and perhaps I can answer
my own question.

> >particle could go neutral, as a direct result of interaction
> >with charged particles in the Van Allen belts,
> I'm confused.. Is your hypothesis saying the particle lost energy
> from outside of the magnetosphere and traveled inwards (maybe
> through the magnetotail or magnetopause) ?

Im the one who is confused. I was thinking of a solid rocket
motor travelling on a parabolic path, the peak of which is lower
than about half an earth radius. I was thinking there was some
mechanism that could accelerate a charged particle from the
exhaust plume and get it up to orbit velocity before its
charge was neutralized by interaction with ions in orbit.

> >trapping a bunch
> >of stuff in orbit, since the neutral junk would not then be carried
> >away by the solar wind. All this from a *suborbital shot*.
> summary: you think that might have a collection of neutral particles
> trapped in the magnetosphere from this suborbital shot ?


> First you need to define for me particle sizes:

OK, a typical solid rocket motor would have every size particle,
from perhaps hundreds of microns down to smoke.

> the submicron radius
> particles take a long time (hours) to reach equilibrium charge potential,
> so they get accelerated quickly out of the Earth's magnetosphere.

Good. {8-]

> The larger particle sizes reflect better the Earth plasma conditions (their
> larger size means larger surface area to the impinging ions and electrons),
> and quickly reach equilibrium charge potential (the charging times vary
> proportional to the size of the particle). The Earth's magnetosphere is
> a very energetic (plasma-wise and magnetic-field-wise) place, and
> particles are charged up constantly.

Im guessing those Matlab scripts you developed for modelling spewing
volcanos on the surface of Io should be adaptable to spewing rocket
motors in a suborbital lob. {8-]

> The people who have done the most work on this topic are Antal Juhász
> and Mihaly Horányi
> Juhász, Antal, and Horányi, Mihaly," (1997), "Dynamics of charged space
> debris in the Earth's plasma environment," J Geophys Res 102,
> pages 7237-7246, April 1, 1997.
> Juhász, Antal, and Horányi, Mihaly," (1999) Magnetospheric Screening
> of Cosmic Dust", J Geophys Res 104, 12577-12583.

Amara, these references bring up a question perhaps far more
important than our discussion of space debris. These references
to Juhász and Horányi are of great use to serious researchers
but not of much use to those like me with just a casual interest
in the topic.

We who use the web a lot are becoming fondly accustomed to
just clicking on a reference instead of going to an actual library
doing actual *work*. {8^D I figure some time in the next few
years, this world will realize we need to get all such research
online, even if it is on pay sites. spike

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