<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>On Sep 29, 2558 BE, at 9:10 PM, spike <<a href="mailto:spike66@att.net">spike66@att.net</a>> wrote:</div><div><br></div><blockquote type="cite"><div><blockquote type="cite"><span>... On Behalf Of Keith Henson</span><br></blockquote><span>Subject: [ExI] A Geophysics problem</span><br><br><blockquote type="cite"><span>...I was explaining the electric propulsion from LEO up to GEO to someone</span><br></blockquote><span>recently and he asked what happens to the 20-25 km/s exhaust. I mentioned</span><br><span>that it was well above escape velocity and he pointed out that it's being</span><br><span>expended in the Earth's magnetic field. That field traps particles with a</span><br><span>lot more energy than this exhaust. I realized that I had no idea what would</span><br><span>happen to the exhaust. I have asked several people, including a PhD from Ad</span><br><span>Astra Rockets. So far nobody has an answer...Keith</span><br><span>_______________________________________________</span><br><span></span><br><span>Interesting question. Before we go into the mass of the particles, since we</span><br><span>are climbing to GEO, the rocket is pointed east so the exhaust is pointed</span><br><span>west. Right hand rule, B increases as we point the thumb north, right hand</span><br><span>rule suggests the magnetic field of the earth diverts the stream upward for</span><br><span>positive charged ions and downward for negative. I think. I need to ponder</span><br><span>that a while longer please.</span><br><span></span><br><span>Cool, time to break out my old friends, Maxwell's equations.</span><br></div></blockquote><br><div>My non-expert guess is the amount is trivial compared with the baseline by three or four orders of magnitude. Still, there might be small regions where it might not be trivial. And, again, we can get some data from existing electric propulsion use as well from neutral exhaust to see how quickly it clears the system.</div><div><br></div><div><div style="line-height: normal;"><span style="line-height: 20px; background-color: rgba(255, 255, 255, 0);">Regards,</span></div><div style="line-height: normal;"><span style="line-height: 20px; background-color: rgba(255, 255, 255, 0);"><br></span></div><div><div style="line-height: normal;"><span style="line-height: 20px; background-color: rgba(255, 255, 255, 0);">Dan</span></div><div style="line-height: normal;"><span style="background-color: rgba(255, 255, 255, 0);"> Sample my Kindle books via:</span></div><div style="line-height: normal;"><a href="http://www.amazon.com/Dan-Ust/e/B00J6HPX8M/" target="_blank" style="background-color: rgba(255, 255, 255, 0);"><font color="#000000">http://www.amazon.com/Dan-Ust/e/B00J6HPX8M/</font></a></div></div></div></body></html>