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http://iopscience.iop.org/0004-637X/501 ... =migration
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D-D Fusion in Jupiter?
D-D Fusion in Jupiter?
Engineering is the art of making what you want from what you can get at a profit.
Jupiter is a tad on the small side to qualify as a brown dwarf by the models in use for the last decade or two, but its excess heat was the inspiration for the concept in the first place.
Our little debate on Low Energy Nuclear Reactions (aka Cold Fusion) could play, too. Alternative pathways for nuclear reactions would change the calculations. Any DD fusion, or D-metal fusion reactions, occurring in Jupiter must depend strongly on the Gamow barrier penetration route (and I see at the beginning of section 2 that is just what they are calculating, but with limited pathways involving He3 and lower).
Or maybe we don't have a clue what radioisotopes are decaying down in its core, or how much gravitational energy it has soaked up in recent eons by eating anything in its way.
Our little debate on Low Energy Nuclear Reactions (aka Cold Fusion) could play, too. Alternative pathways for nuclear reactions would change the calculations. Any DD fusion, or D-metal fusion reactions, occurring in Jupiter must depend strongly on the Gamow barrier penetration route (and I see at the beginning of section 2 that is just what they are calculating, but with limited pathways involving He3 and lower).
Or maybe we don't have a clue what radioisotopes are decaying down in its core, or how much gravitational energy it has soaked up in recent eons by eating anything in its way.
Interesting.
See also my post on DD reactions induced by lightning:
viewtopic.php?p=37668#37668
Clearly, there is gonna be a lot of lightning going on inside Jupiter, so plenty of opportunity for 'electric fusion' rather than thermonuclear.
See also my post on DD reactions induced by lightning:
viewtopic.php?p=37668#37668
Clearly, there is gonna be a lot of lightning going on inside Jupiter, so plenty of opportunity for 'electric fusion' rather than thermonuclear.
OK Chris, do you know enough about Jupiter to duplicate your calculations re. lightning induced fusion for that planet? Its atmosphere is mostly methene, isn't it, much higher pressure. What estimate for number of strikes per second, planet wide? At what energy? -------- I don't even know enough to guess at the questions to ask.
Aero
Old criticism of physics: "Assume a spherical cow."
When the spherical cow model fails to explain observations, then you start to get real.
In this case the cow is spherical, but they assumed a homogeneous cow. The new model has a cow made of layers, but presumed to be well-settled. As Chris points out, we know damned well it is an electric cow.
Aero, I see you get just how complex a cow really is.
With lightning, you have really high voltages, well high enough to achieve conventional hot fusion if you can accelerate particles over a sufficient gradient. In Earth atmosphere, 10 kV per meter, maybe, although it is hard to picture 1 meter free paths for acceleration. But at least you can account for energies far above the eV level where Gamow barrier penetration dominates, so way higher reaction rates possible.
When the spherical cow model fails to explain observations, then you start to get real.
In this case the cow is spherical, but they assumed a homogeneous cow. The new model has a cow made of layers, but presumed to be well-settled. As Chris points out, we know damned well it is an electric cow.
Aero, I see you get just how complex a cow really is.
With lightning, you have really high voltages, well high enough to achieve conventional hot fusion if you can accelerate particles over a sufficient gradient. In Earth atmosphere, 10 kV per meter, maybe, although it is hard to picture 1 meter free paths for acceleration. But at least you can account for energies far above the eV level where Gamow barrier penetration dominates, so way higher reaction rates possible.
Nope. I'd work out how many reactions you'd need to account for the extra heat, and work backwards, making a gesticulation at the end in the general direction of plausibility or otherwise.Aero wrote:OK Chris, do you know enough about Jupiter to duplicate your calculations
Given the large volume and mass of Jupiter, I'd anticipate the outcome would show it is plausible, but that is no proof that it is [all] lightning-induced DD. There will clearly be some such reactions, what fraction of the extra heat is due to it, that'd be guess work.
I certainly don't know enough to even start, and if I had a start I wouldn't know where to go from there, so I'm out.
However, I do have a question. Do you suppose that the calculation has ever been made for Jupiter? If yes then I wonder, by whom? And if no, then what is the risk of making a first estimate? I doubt the estimate will be near 10% of the extra heat but if it is that or higher then it should be looked at closely. If the estimate is orders of magnitude lower than the extra heat, that says something, too.
I looked at wikipedia and found this:
So my previous remark about methane was wrong.
However, I do have a question. Do you suppose that the calculation has ever been made for Jupiter? If yes then I wonder, by whom? And if no, then what is the risk of making a first estimate? I doubt the estimate will be near 10% of the extra heat but if it is that or higher then it should be looked at closely. If the estimate is orders of magnitude lower than the extra heat, that says something, too.
I looked at wikipedia and found this:
http://en.wikipedia.org/wiki/Jupiter#CompositionJupiter's upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume or fraction of gas molecules (see table to the right). Since a helium atom has about four times as much mass as a hydrogen atom, the composition changes when described as the proportion of mass contributed by different atoms. Thus the atmosphere is approximately 75% hydrogen and 24% helium by mass, with the remaining one percent of the mass consisting of other elements. The interior contains denser materials such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass.
So my previous remark about methane was wrong.
Aero