From: Don Kelly <dhky@peeshaw.ca>
Subject: Re: Ground-powered Rocket? Conductive Contrail?
To: sci-physics-plasma@moderators.isc.org
Reply-to: Don Kelly <dhky@peeshaw.ca>
Organization: Shaw Residential Internet
Newsgroups: sci.physics.plasma,sci.energy
References: <cmr1r7$9k4r$1@saturn.cs.uml.edu>


"sanman" <manofsan@yahoo.com> wrote in message
news:cmr1r7$9k4r$1@saturn.cs.uml.edu...
>
> Another silly idea I'd like to ask about -- could a channel of ionized
> gas be used to feed electric current from a ground station to power a
> rocket ascending to orbit?
>
> I've read about femtosecond-pulse lasers being used to create
> persistent conductive channels through the air. They have been used to
> make instant "virtual lightning rods" to divert lightning bolts away
> from skyscrapers or airports, when a storm appears.
>
> If the tremendous electrical power of a lightning bolt can be conveyed
> down such
> an ionized channel from the sky to the ground, then why can't
> electricity be conveyed up it to reach a rocket travelling upwards?

>
> As we just covered before, the atmosphere only extends up a couple of
> dozen miles, but could one perhaps use a rocket's exhaust contrail to
> create a conductive/ionized channel along it? You could then feed
> current from your ground-based power station up that conductive
> channel. (LOL, would sort of give new meaning to the phrase
> "Fly-by-wire"!)
>
> You'd need to keep your conductive exhaust contrail from
> dispersing/dissipating, so you'd be hostage to
> wind/weather/localized-turbulence on the way up. Perhaps you'd use
> Doppler Radar to help you pick the right time and place for good
> launch conditions. But if it only takes about 8 minutes for the
> Shuttle to reach orbit, then using that as a guide, perhaps that's a
> reasonable window for the exhaust contrail to remain cohesive. And if
> it's not a manned payload, perhaps you'd have higher acceleration and
> even quicker travel time to orbit.
>
> (Hmm, I guess they don't have many hydroelectric dams in the Mojave
> Desert, so you'd have to build a nuclear reactor out there. Or perhaps
> a mobile rolling nuclear reactor? Or a ship-borne one, if you're
> launching out at sea?)
>
> Would you absolutely need the laser to make the exhaust contrail
> conductive? It would help, but then you're going to need the exhaust
> contrail to be in a straight line. Perhaps one could select exhaust
> gas(es) that would facilitate the conductivity and also favor staying
> cohesive? If your conductive contrail could work all by itself without
> any ionizing laser to aim, the nice thing about it is that your
> current would just "follow the trail" and always make it to the
> target.
>
> We know that exhaust contrails are often so visible in the sky because
> the exhaust gases condense into little ice crystals in the cold of the
> upper atmosphere. I don't know if this would be a good thing or a bad
> thing. The frozen crystals might fall more quickly, but they'd only
> appear in the atmospheric portion of the contrail, which is vertical
> anyway, so hopefully falling wouldn't distort the contrail shape too
> much. Maybe the passage of enough current would keep the contrail hot,
> and prevent condensation/freezing.
>
> What about a particle beam of accelerated ions? Could that be used as
> a channel for electric current to travel up, instead of the exhaust
> contrail? I know people have suggested microwave beaming, but they
> would be a lot more dangerous to a crew/cargo than electric current,
> IMHO.
>
> So what do you think of these approaches? Has anybody ever suggested
> any of this
> before? What are the shortcomings and difficulties?

Where is the return path for the current? Secondly, if you have this, what
power can be handled for long enough to do any good.? What energy is lost
in the conductive channel?

Note that while the peak power in a lightning stroke is large, it is mainly
dissipated in the conductive channel. If that occurred- not much energy
would be left to power the rocket. (note a lightning stroke transfers a lot
less energy than most think- maybe enough to run a 100 watt bulb for
100hours -worked it out once and came out with an even lower figure)
--
Don Kelly
dhky@peeshaw.ca
remove the urine to answer
>






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