From fission bomb to fusion

  • Thread starter Datafree
  • Start date
  • #1
2
0
How big is the step from a fission bomb to a fusion bomb?Do you simply put H next to some fission bombs?
 

Answers and Replies

  • #2
Astronuc
Staff Emeritus
Science Advisor
18,856
2,121
More or less, one puts some form of hydrogen, e.g. DT, or LiD in a configuration where it was undergo fusion. The fission trigger simply provides the energy used to compress and heat the DT or LiD. At DT can be placed in a fissile device to boost its yield.

The devil is in the details.
 
  • #3
Morbius
Science Advisor
Dearly Missed
1,125
6
How big is the step from a fission bomb to a fusion bomb?Do you simply put H next to some fission bombs?
Datafree,

NOT simple AT ALL!!! It's more difficult than just putting H next to a fission bomb.

As Astronuc points out; the devil is in the details and it took years to figure out how make
a workable hydrogen bomb even though it was conjectured to be possible back during the
Manhattan Project.

If you are interested - read Richard Rhodes book "Dark Sun: The Making of the Hydrogen Bomb"

Dr. Gregory Greenman
Physicist
 
  • #4
2
0
More or less, one puts some form of hydrogen, e.g. DT, or LiD in a configuration where it was undergo fusion. The fission trigger simply provides the energy used to compress and heat the DT or LiD. At DT can be placed in a fissile device to boost its yield.

The devil is in the details.
Datafree,

NOT simple AT ALL!!! It's more difficult than just putting H next to a fission bomb.

As Astronuc points out; the devil is in the details and it took years to figure out how make
a workable hydrogen bomb even though it was conjectured to be possible back during the
Manhattan Project.

If you are interested - read Richard Rhodes book "Dark Sun: The Making of the Hydrogen Bomb"

Dr. Gregory Greenman
Physicist
Thank you.I thought the fission bomb had only to create the heat and pressure of the sun
 
  • #5
Morbius
Science Advisor
Dearly Missed
1,125
6
Thank you.I thought the fission bomb had only to create the heat and pressure of the sun
Datafree,

Just having heat and pressure may not give you what you want. It's like saying all you need to fly
is to run down the runway real fast and you will lift off. NOPE - you have to have a wing that can
make use of that velocity and turn it into lift.

Likewise, with a thermonuclear bomb - you have to have a configuration that can make use of the
heat and pressure. Just having heat and pressure is NOT sufficient.

Dr. Gregory Greenman
Physicist
 
  • #6
5,601
40
Kip Thorne in BLACK HOLES AND TIME WARPS has an historical discussion of the development of fission and fusion bombs...
He explains the first Soviet "hydrogen" bomb was really a souped up fission bomb....but they came acroos LiD before the US....and he also discusses how the two atomic (fission) bombs dropped on Japan were of two different material designs...U235 first then plutonium for the second....
 
  • #7
400
1
How big is the step from a fission bomb to a fusion bomb?Do you simply put H next to some fission bombs?
Yes, it's really just as simple as that. :smile: No one who actually knows anything about this stuff can or should comment.
 
  • #8
Morbius
Science Advisor
Dearly Missed
1,125
6
Yes, it's really just as simple as that. :smile: No one who actually knows anything about this stuff can or should comment.
Jeff,

You CAN tell them what the Department of Energy has released.

In fact, you can find the Dept of Energy statement saying EXACTLY what I've
stated in Richard Rhodes' book!!!

Dr. Gregory Greenman
Physicist
 
  • #9
400
1
Greg, did you have your posts formally ADC'd?

Jeff,

You CAN tell them what the Department of Energy has released.

In fact, you can find the Dept of Energy statement saying EXACTLY what I've
stated in Richard Rhodes' book!!!

Dr. Gregory Greenman
Physicist
 
  • #10
Morbius
Science Advisor
Dearly Missed
1,125
6
Greg, did you have your posts formally ADC'd?
Jeff,

I AM an ADC!!

Like I said - you can ALWAYS refer to official statements by DOE.

Dr. Gregory Greenman
 
  • #11
400
1
My concern is your reference to a book for more information, which could be construed to imply some kind of official blessing. I have no idea what is in the book, I've never read it, but as you must know it could potentially skirt the line.
 
  • #12
vanesch
Staff Emeritus
Science Advisor
Gold Member
5,028
16
My concern is your reference to a book for more information, which could be construed to imply some kind of official blessing. I have no idea what is in the book, I've never read it, but as you must know it could potentially skirt the line.
No, not really. The book is out there, you can find it in every good library, you can order it on amazon and all that. I really think it doesn't contain any undisclosed material. I've read it, and it contains far more detailled information than what Greg said here - and one can also imagine that it is still far from containing useful design information to quickly make a bomb. It is an interesting story of physics too. To summarise the argument: the "naive" idea that the fission bomb materially (hydrodynamically) compresses and heats the hydrogen was the wrong way, and led people astray for a while. The actual idea that worked was to use *radiative pressure*. This sounds crazy at first, as radiative pressure seems to be quite elusive as compared to hydrodynamical pressure - for matter in normal circumstances. But it turns out that in the thermodynamical states one is interested in, radiative pressure is far stronger than hydrodynamical pressure, and moreover can be much better concentrated.
This is explained in much more detail in Rhodes' book.
 
  • #13
4,239
1
Thank you.I thought the fission bomb had only to create the heat and pressure of the sun
Heat, pressure and duration.
 

Related Threads on From fission bomb to fusion

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
16
Views
5K
  • Last Post
Replies
1
Views
2K
  • Last Post
3
Replies
57
Views
17K
Replies
13
Views
8K
Replies
7
Views
3K
  • Last Post
Replies
9
Views
4K
  • Last Post
Replies
6
Views
2K
Replies
7
Views
5K
  • Last Post
2
Replies
31
Views
48K
Top