Lower threshold of mA for fusion
Lower threshold of mA for fusion
Whats the lowest amperage required for fusion within a fusor?
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Frank Sanns
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Re: Lower threshold of mA for fusion
Elementary charge is 1.6 E-19 coulombs and an ampere is a coulomb per second. The minium current to have fusion in a targeted system is then 1.6 E-19 amperes during the second in which the collision occurs. This is assuming the same moving charge will provide the ionization and the current to move a deuterion to a resonable fusion energy of 20 KV or more.
To use the benefit of a fusor, a charge located on opposite sides of the inner grid must move which is double the elementary charge. That puts the current at 3.2 E -19 amperes using the same assumptions as above.
If you are using neutron detection as verification of fusion, you would need double this current since only half of the fusion reactions with deuteruim alone will produce a neutron.
These are the lowest currents to produce fusion but there are some other factors that need to be considered. Not all currents will produce ionizations or ionizations the proper distance out from the inner grid. This will add a couple of orders of magnitude more to your current. The tally now is something on the order of 1 E -16 amperes.
One mole of deuterium is 6.02 E 23 atoms per 22,400 cc. Inside a fusor the pressure is on the order of 15 E -3 torr. At this chamber pressure the number deuterium atoms are 5.3 E 14 atoms per cc. This sounds like a big number and it is but the space in between the atoms is also a big number. Estimating the nearest neighbor then is the cube root of that which is 8 E 4 atoms per cm. One over that number gives the spacing as 1 atom every 1 E-7 meters. Atomic diameters are on the order of 1 E -10 meters and nucleus diameters are on the order of 1 E -15 meters. In a fusor then, deuterons of 1 E -15 meters are being hurled at other deuterons that are 1 E -7 meters apart. The next atom would be E-7 / E -15 = E 8 times away. Scaling this to the macro world for understanding, assume that a nucleus were 1 cm in diameter (a little under half an inch). This puts its nearest neighbor at 1 million meters (450 miles) away.
Since there is 1 E 8 times more space than there are nucleii, the chance of something colliding is pretty bleak. Multiplying ampere tally of 1 E -16 times the space between crudely puts the current at 1 E -8 amperes for the miminum current to expect one fusion event per second.
This current excludes non productive collisions, near misses, grid wire collisions, collisions with other gasses in the chamber, actual fusion cross sections, ability to detect neturons or other fusion byproducts, etc.
With an ultra clean chamber of good design and a He3 detector 1 E 3 neutrons per second (isotropic) are easily detectable. Using all of the above assumptions backed up by my personal experimental evidence, the minium current to do easily verifiable fusion is on the order of 1 E -4 amperes ( 0.1 milliamperes) at 20 KV.
For somebody with no experience with a fusor AND detection equipment the number is probably 10 times higher. If somebody were just getting started, they should not really attempt fusion without a power supply capable of at least a couple of millamps current.
Frank S.
To use the benefit of a fusor, a charge located on opposite sides of the inner grid must move which is double the elementary charge. That puts the current at 3.2 E -19 amperes using the same assumptions as above.
If you are using neutron detection as verification of fusion, you would need double this current since only half of the fusion reactions with deuteruim alone will produce a neutron.
These are the lowest currents to produce fusion but there are some other factors that need to be considered. Not all currents will produce ionizations or ionizations the proper distance out from the inner grid. This will add a couple of orders of magnitude more to your current. The tally now is something on the order of 1 E -16 amperes.
One mole of deuterium is 6.02 E 23 atoms per 22,400 cc. Inside a fusor the pressure is on the order of 15 E -3 torr. At this chamber pressure the number deuterium atoms are 5.3 E 14 atoms per cc. This sounds like a big number and it is but the space in between the atoms is also a big number. Estimating the nearest neighbor then is the cube root of that which is 8 E 4 atoms per cm. One over that number gives the spacing as 1 atom every 1 E-7 meters. Atomic diameters are on the order of 1 E -10 meters and nucleus diameters are on the order of 1 E -15 meters. In a fusor then, deuterons of 1 E -15 meters are being hurled at other deuterons that are 1 E -7 meters apart. The next atom would be E-7 / E -15 = E 8 times away. Scaling this to the macro world for understanding, assume that a nucleus were 1 cm in diameter (a little under half an inch). This puts its nearest neighbor at 1 million meters (450 miles) away.
Since there is 1 E 8 times more space than there are nucleii, the chance of something colliding is pretty bleak. Multiplying ampere tally of 1 E -16 times the space between crudely puts the current at 1 E -8 amperes for the miminum current to expect one fusion event per second.
This current excludes non productive collisions, near misses, grid wire collisions, collisions with other gasses in the chamber, actual fusion cross sections, ability to detect neturons or other fusion byproducts, etc.
With an ultra clean chamber of good design and a He3 detector 1 E 3 neutrons per second (isotropic) are easily detectable. Using all of the above assumptions backed up by my personal experimental evidence, the minium current to do easily verifiable fusion is on the order of 1 E -4 amperes ( 0.1 milliamperes) at 20 KV.
For somebody with no experience with a fusor AND detection equipment the number is probably 10 times higher. If somebody were just getting started, they should not really attempt fusion without a power supply capable of at least a couple of millamps current.
Frank S.
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Richard Hull
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Re: Lower threshold of mA for fusion
Wow! I could not have written a reply that could have topped Frank's reply, in that it is 100% detailed and accurate while still being smug at the core level of two particles can do fusion.
The real beauty is that the real world, in so many different ways, constantly bites one's ass. This is carefully explained in steps (bites of ass) such that, in the end, fusion goes from a minimum honest fusion current of 10e-19 amps up by a factor of full 10 quadrillion times if you are an amateur, using amateur instruments to prove you have really done fusion.
What a glorious dichotmy between theory and "the doing". This points out the great gulf affixed between thought experiments and engineering to get results in the real world. From 0.1 attoamp to 1-10 milliamps.......This is the range between where fusion can actually begin and where you can really show fusion happening at the amateur level.
You should repost this as an FAQ, Frank! Make sure that you title it " FAQ - The lowest current needed to do fusion"........... It might go better under the construction forum or the fusion theory forum.
If you do not make a FAQ out of it, I will, but give you full credit....I'd rather it be under your name though.
Richard Hull
The real beauty is that the real world, in so many different ways, constantly bites one's ass. This is carefully explained in steps (bites of ass) such that, in the end, fusion goes from a minimum honest fusion current of 10e-19 amps up by a factor of full 10 quadrillion times if you are an amateur, using amateur instruments to prove you have really done fusion.
What a glorious dichotmy between theory and "the doing". This points out the great gulf affixed between thought experiments and engineering to get results in the real world. From 0.1 attoamp to 1-10 milliamps.......This is the range between where fusion can actually begin and where you can really show fusion happening at the amateur level.
You should repost this as an FAQ, Frank! Make sure that you title it " FAQ - The lowest current needed to do fusion"........... It might go better under the construction forum or the fusion theory forum.
If you do not make a FAQ out of it, I will, but give you full credit....I'd rather it be under your name though.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Re: Lower threshold of mA for fusion
Ive posted it up on the FAQs!