Actually I'm a mechanical Engineer but you made me so regret of myself why I didnt chose physics instead of Engineering. You are so amazing teacher and your students are really lucky persons. . Thank you so much again for posting this type of very informative material. DrPhysics A You are incredible person .
In the D-D reaction, there is both proton branching and neutron branching. You should also explain the cat-D reaction, banana orbits, and possibly a video on direct conversion. Another video idea would be to explain the different types of fusion devices, ie tokamaks, stellarators, mirrors, DPF, spheromaks, etc.
I see that you stopped the project a long ago. But I'd like to thank you today for all your efforts and time! It was really great and it remains great!
8:18 - 3ktn, where n is the total number of atoms. Atoms? I thought it is the total number of particles as we split the atoms to individual particles, as they are all ionized in a plasma.
A couple of errors that I find concerning. In describing D-D v D-T reactions, you say there is no radioactivity generated. But neutrons come off; in fact, they carry most of the energy. Those neutrons collide with the reactor walls, and induce radioactivity. True, the materials can be chosen so as to not have long-lived products. But there is actually intense radioactivity induced, and it's a big problem. The other error is that Bremsstrahlung is not just wasted energy. It eventually shows up as heat, just like the neutron captures that absorb most of the reaction energy. So it's not really wasted at all. It's just that it bleeds off energy that is needed to sustain the reaction.
I really enjoy your videos. Great info and you have an effective way of explaining complex topics In a way which is easy to grasp. I wish more professors were like you.
I did my a levels ages ago this video helps me to review what I use to know and its fun know more may be a bit more on foundation really hope down to ur comments
regretfully the author of these excellent videos has died of old age by now, or else is around 80 years old in 2023......as a non-physicist i was able to follow along with his ideas due to his excellent cogent and economical teaching method.......he has described the perfect Romeo and Juliet scenario of modern physics where we know what we want, we can see it, and can describe it perfectly and have worked and planned very hard to get to this exquisite point of understanding and have put almost everything in place....BUT....our true love affair with nuclear fusion energy is doomed to be eternally unrequited and have no happily ever after ending, no matter how much additional energy and time and analysis and planning we put into it. we have learned everything we can about it only to demonstrate to ourselves why we cannot actually locally recreate the sun in a controlled useful way, something we already knew before we started this long journey.....just as Shakespeare knew Romeo and Juliet would die in each other's arms without ever being able to achieve their goal of unending true love before he ever began to write the play.....but the journey has been heroic and magnificent and worthwhile in itself even though we will never get to the final destination alive in this life. The author says we (qua parts) all came from the inside of a sun and as parts we might all return to some new sun in some future time but we will never metaphorically hold that sun in the palm of our hands or make it sit up and bark like a trained dog.
The notion that a fusion plasma can melt its container upon contact is not accurate. It is indeed an urban legend or a misconception that has been perpetuated in popular culture.
The Jetter Cycle initiates the fusion reaction with neutron bombardment of Li6 since the Li6+n reaction produce He4 + T + 4.8 MeV - which is way more than required to initiate the T + D reaction. So, if you start out with Li6D in a molten salt along with Zn69 which takes energetic n and produces 2n and Cu68 via the (n,2n) reaction - and put a neutron blanket over the molten salt (and zinc) - you start the reaction with a neutron starter and it grows until you lose the same number of neutrons you generate - and you have a molten salt subcritical blanket reactor with a Li6D fuel. Now if you use (n,2n) material that takes a while to complete the reaction - turning your energetic neutrons into two low energy neutrons - or at least a portion of them - you build your reaction with no possibility of a hydrogen bomb explosion since it takes too long (Zinc takes 28 minutes half life to decay releasing 2n after absorbing n) .
In the original fusion criterion proposed (1955), JD Lawson includes losses due to Bremsstrahlung but deliberately neglects system losses. If the complete energy balance is accounted for, the return on energy invested (Q) looks even worse. If a complete energy balance is not accounted for, then failure to achieve fusion power is due to fuzzy accounting not engineering and the consequence that fusion power will remain 20 years away indefinitely.
Why dont they spin the plasma around an axis like an spinning ball? wouldn't this reduce the size of the magnetic field needed (which would result in lower energy input)? if you heat it up with lasers they would have to be pointing through the spinning axes. sorry for my bad english
As a German i love to hear germanizisms pronounced by native english speakers. Took me a moment to realize that you meant Bremsstrahlung :D espacially the first time you say it. But after that it was great fun even more than the actual physics :D
even dough i dont have to learn this things for my exams(in my country turkey) i watch and learn some interesting things from your videos. thanks a lot
I am an eight grade student and I am doing what I can from what I understand here, I don't understand the factor sigma v portion. I believe this is the measure of velocity, but you said you "crossed" the x and the y but I have no idea how it is a "factor" and I don't know to what value or what sigma stands for. please excuse my ignorance, I have just begun 11th grade physics recently and I only know the basics
No fission splits big atoms and fusion fuses smaller atoms, but they are both different types of nuclear reactors. But fission have been more successful so far.
+sparkstarter the fact that any decent fusion reactor need a strong magnetic field to be maintained and also needs massive amount of energy to kick start any decent fusion reaction.
+LittleHorhey I know the main problem is plasma confinement, just wondering if we could get a high level engineering review of what has been tried and why it has failed.
sparkstarter Sandia national lab has achieved fusion, even leading to superheavy nuclei twice the mass of uranium. But even for them I think the issue is that the energy out is less than the energy needed to initiate z pinch in wires via plasma.
Great video once again. There's one thing I'm not sure I agree with: you say that if we figure out a commercial fusion reactor we'll satisfy our energy needs for millions of years. Is that not assuming a zero growth rate? If you assume the current growth rate (say 2%?) in energy use, something that would have lasted a million years will only last about 500 years, no? And one could argue that energy growth rate might go up if we get a great source like fusion working. Am I wrong?
DrPhysicsA Thanks. My point is that exponential growth is such a big deal that even something as abundant as deuterium wouldn't last nearly as long as one would think. Try out the calculation assuming 2% growth, even without the lithium limiting factor. Maybe it would make a good short video?
Actually I'm a mechanical Engineer but you made me so regret of myself why I didnt chose physics instead of Engineering.
You are so amazing teacher and your students are really lucky persons.
. Thank you so much again for posting this type of very informative material.
DrPhysics A You are incredible person .
Don't be sad, you are the one who can help construct the efficient nuclear fusion reaction with engineering tricks !
In the D-D reaction, there is both proton branching and neutron branching. You should also explain the cat-D reaction, banana orbits, and possibly a video on direct conversion. Another video idea would be to explain the different types of fusion devices, ie tokamaks, stellarators, mirrors, DPF, spheromaks, etc.
GucciManeSaysBURR mirrors. That reminds me of ironman 2
I see that you stopped the project a long ago. But I'd like to thank you today for all your efforts and time! It was really great and it remains great!
8:18 - 3ktn, where n is the total number of atoms. Atoms? I thought it is the total number of particles as we split the atoms to individual particles, as they are all ionized in a plasma.
Thanku sir . Your videos helps a lot . Could you please upload videos on parity and its applications. We would be very grateful to you.
A couple of errors that I find concerning. In describing D-D v D-T reactions, you say there is no radioactivity generated. But neutrons come off; in fact, they carry most of the energy. Those neutrons collide with the reactor walls, and induce radioactivity. True, the materials can be chosen so as to not have long-lived products. But there is actually intense radioactivity induced, and it's a big problem.
The other error is that Bremsstrahlung is not just wasted energy. It eventually shows up as heat, just like the neutron captures that absorb most of the reaction energy. So it's not really wasted at all. It's just that it bleeds off energy that is needed to sustain the reaction.
I really enjoy your videos. Great info and you have an effective way of explaining complex topics In a way which is easy to grasp. I wish more professors were like you.
I did my a levels ages ago this video helps me to review what I use to know and its fun know more may be a bit more on foundation really hope down to ur comments
regretfully the author of these excellent videos has died of old age by now, or else is around 80 years old in 2023......as a non-physicist i was able to follow along with his ideas due to his excellent cogent and economical teaching method.......he has described the perfect Romeo and Juliet scenario of modern physics where we know what we want, we can see it, and can describe it perfectly and have worked and planned very hard to get to this exquisite point of understanding and have put almost everything in place....BUT....our true love affair with nuclear fusion energy is doomed to be eternally unrequited and have no happily ever after ending, no matter how much additional energy and time and analysis and planning we put into it.
we have learned everything we can about it only to demonstrate to ourselves why we cannot actually locally recreate the sun in a controlled useful way, something we already knew before we started this long journey.....just as Shakespeare knew Romeo and Juliet would die in each other's arms without ever being able to achieve their goal of unending true love before he ever began to write the play.....but the journey has been heroic and magnificent and worthwhile in itself even though we will never get to the final destination alive in this life. The author says we (qua parts) all came from the inside of a sun and as parts we might all return to some new sun in some future time but we will never metaphorically hold that sun in the palm of our hands or make it sit up and bark like a trained dog.
could we have topological applications in sloving problems in economics , physics and engineering ??
and the other some but not spectrums and frequency's can be captured and converted to electricity bosting efficiency
You kind of saved my ass big time. Thank you so much, your awesome.
mmm torus (drools)
O.K.Howis the energy extracted from this hot reaction in a torus?
The notion that a fusion plasma can melt its container upon contact is not accurate. It is indeed an urban legend or a misconception that has been perpetuated in popular culture.
The Jetter Cycle initiates the fusion reaction with neutron bombardment of Li6 since the Li6+n reaction produce He4 + T + 4.8 MeV - which is way more than required to initiate the T + D reaction. So, if you start out with Li6D in a molten salt along with Zn69 which takes energetic n and produces 2n and Cu68 via the (n,2n) reaction - and put a neutron blanket over the molten salt (and zinc) - you start the reaction with a neutron starter and it grows until you lose the same number of neutrons you generate - and you have a molten salt subcritical blanket reactor with a Li6D fuel.
Now if you use (n,2n) material that takes a while to complete the reaction - turning your energetic neutrons into two low energy neutrons - or at least a portion of them - you build your reaction with no possibility of a hydrogen bomb explosion since it takes too long (Zinc takes 28 minutes half life to decay releasing 2n after absorbing n) .
Im starting nuclear engineering in a month. Just having a taste of whats to come
Excellent lecture, Dr. PhysicsA.
In the original fusion criterion proposed (1955), JD Lawson includes losses due to Bremsstrahlung but deliberately neglects system losses. If the complete energy balance is accounted for, the return on energy invested (Q) looks even worse. If a complete energy balance is not accounted for, then failure to achieve fusion power is due to fuzzy accounting not engineering and the consequence that fusion power will remain 20 years away indefinitely.
All good and interesting scientific research, but I will still put my bets on wind, solar, and storage for the next two decades
Why dont they spin the plasma around an axis like an spinning ball? wouldn't this reduce the size of the magnetic field needed (which would result in lower energy input)? if you heat it up with lasers they would have to be pointing through the spinning axes. sorry for my bad english
Have you considered hydrogen boron fusion?
As a German i love to hear germanizisms pronounced by native english speakers. Took me a moment to realize that you meant Bremsstrahlung :D espacially the first time you say it. But after that it was great fun even more than the actual physics :D
even dough i dont have to learn this things for my exams(in my country turkey) i watch and learn some interesting things from your videos. thanks a lot
Thx Dr allways nice to see your work. Did you made a video explaining the major engeneering problems on the fusion reactor?
Does anyone really want a successful nuclear fusion reactor I mean besides those poor people that pay for electric
taught us how to do a nuclear bomb from zero
Also couldn't you just have solar panels in the fusion device to catch the photons and produce electricity that way?
that British accent though
👍
I am an eight grade student and I am doing what I can from what I understand here, I don't understand the factor sigma v portion. I believe this is the measure of velocity, but you said you "crossed" the x and the y but I have no idea how it is a "factor" and I don't know to what value or what sigma stands for. please excuse my ignorance, I have just begun 11th grade physics recently and I only know the basics
+Wake Monroe Build solid understanding of basics instead of trying to grasp advanced topics and make possibly wrong assumptions in your head.
Why is it that every generator is about boiling water lol?
Steam turbines are still one of the most common ways of creating usable electricity from a thermal energy source.
Nuclear fusion reactor or nuclear reactor are same??
No fission splits big atoms and fusion fuses smaller atoms, but they are both different types of nuclear reactors. But fission have been more successful so far.
Oh boy..
What are the engineering problems that will take 20 years to solve?
+sparkstarter the fact that any decent fusion reactor need a strong magnetic field to be maintained and also needs massive amount of energy to kick start any decent fusion reaction.
+LittleHorhey I know the main problem is plasma confinement, just wondering if we could get a high level engineering review of what has been tried and why it has failed.
sparkstarter Sandia national lab has achieved fusion, even leading to superheavy nuclei twice the mass of uranium. But even for them I think the issue is that the energy out is less than the energy needed to initiate z pinch in wires via plasma.
thank you
one of the best lecturer in the world
Great video once again. There's one thing I'm not sure I agree with: you say that if we figure out a commercial fusion reactor we'll satisfy our energy needs for millions of years. Is that not assuming a zero growth rate? If you assume the current growth rate (say 2%?) in energy use, something that would have lasted a million years will only last about 500 years, no? And one could argue that energy growth rate might go up if we get a great source like fusion working. Am I wrong?
Well there's a lot of deuterium in the sea, so it may be that Lithium would be the limiting factor.
DrPhysicsA
Thanks. My point is that exponential growth is such a big deal that even something as abundant as deuterium wouldn't last nearly as long as one would think. Try out the calculation assuming 2% growth, even without the lithium limiting factor. Maybe it would make a good short video?
+maitland1007 With Moore's and the corresponding advances in efficiency?
Your brilliant
What about his brilliant?
Roving Punster You just had to share your opinion didn't you? As if it mattered.
^ you must be fun at parties.
I'm actually the center of attention. :) thank you, you must be very observant of truth.
I meant this roving punster buzz kill guy but whatever
you are my hero m8 :)
Thank you so much for your videos!
I have been following it for two years, but where is it going?
yay! ive been waiting for that for a long time! thank you! ^.^
Omg bro 😳
Why aren't we making ball shaped reactors, instead of doughnut shaped?
Tobias Henriksen because the magnetic field can't work to make it into a sphere
Something along those lines has been tried, although I don't know how it has worked out. As you might imagine, it's called a…spheromak.