Quote from: Downix on 12/13/2009 12:16 pmQuote from: clongton on 12/13/2009 12:09 pmQuote from: hop on 12/13/2009 07:21 amQuote from: clongton on 12/13/2009 06:35 amStars dump heat radiatively. Is there no way to duplicate that process for a deep space vehicle?WTH ? A star does this by being made entirely of hot plasma, having enough gravity to hold together in that state, and generally not caring what gets cooked.I KNOW how stars do it. I was asking if there had been any thinking among the physicists out there of any way to duplicate, at least in principle, what the star does for an end result. It was a think-outside-the-box question.Yes, the issue comes in energy-in vs energy-out. The Farnsworth Fusor does a fair impersonation of a star, it just consumed more than it could ever generate.I'm familiar with inertial electrostatic confinement. It's an attempt to create a fusion reactor. That's not what I was getting at. I was asking about ways to dump waste heat. Any fusion reactor we build is going to have a tremendous waste heat problem. The question is how do we dump it without melting the spacecraft? I was looking for innovative ideas other than huge honking radiators. Maybe we can create a plasma confinement radiator that can be as large as we need it that just switches on whenever the reactor is running. That's just a wild ass thought I thought I'd throw out there. Does everything we build actually have to be solid matter?
Quote from: clongton on 12/13/2009 12:09 pmQuote from: hop on 12/13/2009 07:21 amQuote from: clongton on 12/13/2009 06:35 amStars dump heat radiatively. Is there no way to duplicate that process for a deep space vehicle?WTH ? A star does this by being made entirely of hot plasma, having enough gravity to hold together in that state, and generally not caring what gets cooked.I KNOW how stars do it. I was asking if there had been any thinking among the physicists out there of any way to duplicate, at least in principle, what the star does for an end result. It was a think-outside-the-box question.Yes, the issue comes in energy-in vs energy-out. The Farnsworth Fusor does a fair impersonation of a star, it just consumed more than it could ever generate.
Quote from: hop on 12/13/2009 07:21 amQuote from: clongton on 12/13/2009 06:35 amStars dump heat radiatively. Is there no way to duplicate that process for a deep space vehicle?WTH ? A star does this by being made entirely of hot plasma, having enough gravity to hold together in that state, and generally not caring what gets cooked.I KNOW how stars do it. I was asking if there had been any thinking among the physicists out there of any way to duplicate, at least in principle, what the star does for an end result. It was a think-outside-the-box question.
Quote from: clongton on 12/13/2009 06:35 amStars dump heat radiatively. Is there no way to duplicate that process for a deep space vehicle?WTH ? A star does this by being made entirely of hot plasma, having enough gravity to hold together in that state, and generally not caring what gets cooked.
Stars dump heat radiatively. Is there no way to duplicate that process for a deep space vehicle?
So any inter-planetary polywell fusion vehicle is going to use some amount of reaction mass, probably LH2. There's your cooling mechanism right there.
Here's a wild idea. How about using the plasma as lasing medium and ejecting waste heat as a laser? I've seen similar ideas based on laser cooling.
Quote from: kkattula on 12/14/2009 12:03 amSo any inter-planetary polywell fusion vehicle is going to use some amount of reaction mass, probably LH2. There's your cooling mechanism right there....no.Assume you can get the coolant up to 3000 K (maybe a bit optimistic - okay, a lot optimistic, but whatever).Starting from 20 K, that's 48.3 MJ/kg, if my calculations are correct. Multiply by five for the total energy imparted to the propellant from a reactor with an 80% direct-conversion efficiency (so the previous figure is 20% of the total output). Assume 100% jet power efficiency. Then back-calculate a specific impulse.2241 seconds.Do you really want to limit your interplanetary spacecraft to that?
Fusion electric QED engines typically have 2 < [F] < 6 and 1500 < Isp < 5500 sec
Two approaches can be followed for QED engine configurations. First is an all regeneratively cooled [ARC] system, in which that fraction of the fusion power not delivered to the e-beam and deposited into the propellant gas is taken up by the in-flowing propellant stream before entering the thrust chamber. Second is a system that utilizes a separate waste heat radiator ... for controlled-space-radiation [CSR] cooling to handle some specified fraction of the regenerative cooling requirement.
Is there some rough set of equations that ties all the parameters and variables together? They don't have to be accurate, I'm just curious to see the full picture of all things involved.
Can anybody please point me to an article related to fusion propulsion by means of plasma shockwave compression? I have ran through some numbers and it seems a ramjet vehicle traveling at Mach 10 through the lower layer of the Jovian Hydrogen atmosphere would develop the sufficient pressure/temperature across the plasma shockwave to generate steady fusion and expel Helium. This is not like a Bussard ramjet since it travels through much thicker Hydrogen and is solely based on compressed sound waves in the plasma.Thanks.
The EMC2 website has been updated.http://www.emc2fusion.org/
So that is what, 7.8 meters on a side? Assuming the man is 6 ft. tall.