Nuclear weapons for anti-missile defense

[Morbius]

Extremely short time is not a problem. X-rays move with the speed of light. That's very, very fast: 30 cm/nanosecond. Even if X-ray photon on average needs dozens of reflections before it finds the radiation window, it still takes just a few nanoseconds.

So, how many nanoseconds do we have?

nikkom,

You tell me. You are the one that wants an anisotropic source. I'm just saying that since any anisotropy is going to be extremely short lived, then for all intents and purposes, it didn't happen

The plasma does not need to absord the radiation. It is sufficient to reflect it. If the casing is made of high-Z materials, the plasma will stay opaque to the X-rays: they will be strongly scattered off it. This also means that not the entire casing turns to plasma at once - its inner few millimeters do so first, and then this plasma shields the rest for a short time.

100% WRONG! You don't get to decide whether the X-rays and gamma rays are going to reflect or be absorbed, Mother Nature makes that decision. Unfortunately for your hypothesis, reflection is a collective phenomenon of multiple atoms. However, the wavelengths of the high energy X-rays and gamma rays are too short; . That's why we don't have X-ray and gamma-ray mirrors modulo some relatively weak reflection at grazing angles for low energy X-rays.

TOTALLY 100% WRONG about the plasma "shielding". I can see you've NEVER studied plasma physics.

That's exactly how second stage of fusion device works: high-Z lined casing keeps a "sea" of X-rays contained, so that they are used to ablatively compress the secondary. It works: radiation manages to compress the secondary before casing "burns through".

Yes - I know how that works.
Gregory

 

[nikkkom]

nikkom,

You tell me. You are the one that wants an anisotropic source. I'm just saying that since any anisotropy is going to be extremely short lived, then for all intents and purposes, it didn't happen

I told it already. With 0.5 cm thick high-Z casing, we have several hundreds of nanoseconds before casing stops containing X-ray "photon soup".

100% WRONG! You don't get to decide whether the X-rays and gamma rays are going to reflect or be absorbed, Mother Nature makes that decision. Unfortunately for your hypothesis, reflection is a collective phenomenon of multiple atoms. However, the wavelengths of the high energy X-rays and gamma rays are too short; . That's why we don't have X-ray and gamma-ray mirrors modulo some relatively weak reflection at grazing angles for low energy X-rays.

There is no need to shout.

I didn't mean reflection as in a mirror. Scattering and re-radiation will do. And *it does* in the fusion device. High-Z plasma is opaque to X-rays. They get absorbed and re-radiated by it, impeding radiative energy transfer through casing.

TOTALLY 100% WRONG about the plasma "shielding". I can see you've NEVER studied plasma physics.

And also, each and every fusion bomb test is a fake. Right...

 

[Morbius]

I told it already. With 0.5 cm thick high-Z casing, we have several hundreds of nanoseconds before casing stops containing X-ray "photon soup".

nikksom,

Sorry - but your "calculation" is WAY, WAY TOO SIMPLISTIC. The physics is much more complex.

I didn't mean reflection as in a mirror. Scattering and re-radiation will do.

Scatter and re-radiation are NOT reflection. Heck you don't even know the vocabulary let alone how to do detailed calculations and simulation. When scientists mean scatter and re-radiation, they call it "scatter" and "re-radiation" and not "reflection".

And *it does* in the fusion device. High-Z plasma is opaque to X-rays. They get absorbed and re-radiated by it, impeding radiative energy transfer through casing.

This is where you don't know your plasma physics. High-Z solids are opaque, as are plasmas that have been compressed above what is called the "critical density". But EM radiation goes through plasma below the critical density. That's why I said it will only work the way you "think" it is going to work for an extremely short time. Not all the energy is re-radiated; and the energy that is not re-radiated is absorbed and turns the material from a high-Z solid to a high-Z low-density plasma that no longer has high opacity.

Enhanced x-ray emissions from low-density high-Z mixture plasmas generated with intense nanosecond laser

http://www.sciencedirect.com/science/article/pii/S0375960114000760

I would also recommend the classic text "Phyics of Fully Ionized Gases" by Lyman Spitzer.

And also, each and every fusion bomb test is a fake. Right...

By what stretch of "logical" reasoning did you come up with THAT?

Instead of discussing large "nuclear devices"; let's look at another topic which is ICF - Inertial Confinement Fusion. The re-radiation idea you espouse above is used in ICF. For example, I refer you to this Wikipedia entry:

http://en.wikipedia.org/wiki/Hohlraum

The indirect drive approach to inertial confinement fusion is as follows; the fusion fuel capsule is held inside a cylindrical hohlraum. The radiation source (e.g., laser) is pointed at the interior of the hohlraum, which absorbs and re-radiates the energy as X-rays, rather than on the capsule itself, a process known as indirect drive. The advantage to this approach is that the energy is re-radiated in a much more symmetric fashion than would be possible in the direct drive approach, resulting in a more uniform implosion.

The X-ray intensity around the capsule must be very symmetrical to avoid hydrodynamic instabilities during compression.

Gregory

 

[nikkkom]

nikksom,

Sorry - but your "calculation" is WAY, WAY TOO SIMPLISTIC. The physics is much more complex.

Okay. You are a specialist here, please start using numbers. I, a layman, already gave some numbers in my posts. Tell me which of my numbers are wrong. Give yours.

> And *it does* in the fusion device. High-Z plasma is opaque to X-rays. They get absorbed and re-radiated by it, impeding radiative energy transfer through casing.

This is where you don't know your plasma physics.

Indeed I'm not plasma physicist. However, I do know that fusion bombs use radiation implosion, that radiation for that purpose is contained by high-Z lined casing. It's public knowledge now. Am I wrong about that?

High-Z solids are opaque, as are plasmas that have been compressed above what is called the "critical density". But EM radiation goes through plasma below the critical density. That's why I said it will only work the way you "think" it is going to work for an extremely short time. Not all the energy is re-radiated; and the energy that is not re-radiated is absorbed and turns the material from a high-Z solid to a high-Z low-density plasma that no longer has high opacity.

Numbers please. How many nanoseconds plasma needs to expand to transparency after it gets heated by X-rays? I'm not asking you to reveal any secrets. Data from publicly-available sources such as NWFAQ will suffice.

 

[Morbius]

Okay. You are a specialist here, please start using numbers. I, a layman, already gave some numbers in my posts. Tell me which of my numbers are wrong. Give yours.

Indeed I'm not plasma physicist. However, I do know that fusion bombs use radiation implosion, that radiation for that purpose is contained by high-Z lined casing. It's public knowledge now. Am I wrong about that?

Numbers please. How many nanoseconds plasma needs to expand to transparency after it gets heated by X-rays? I'm not asking you to reveal any secrets. Data from publicly-available sources such as NWFAQ will suffice.

nikkom,

I am not commenting on anything in the NWFAQ.

I'm just saying that you aren't going to have some high-Z material stay opaque for 100 nanoseconds or more to provide your radiation "beam". In very short order, that is on very short time scales much, much less than your 100 nanoseconds ( 0.1 microsecond ); your high-Z material is going to be a low-density plasma that won't do what you think it is going to do.

Gregory

 

[nikkkom]

nikkom,

I can't comment on ANYTHING; even information that has been publicly released. I can't comment on anything in the NWFAQ.

I'm just saying that you aren't going to have some high-Z material stay opaque for 100 nanoseconds or more to provide your radiation "beam".

Okay. The numbers for fusion device I learned from public sources:

* generation of X-rays in 1st (fission) stage: ~50 nanoseconds.
* arrival of X-rays, thermalization of tamper and casing surface: 10 ns.
(As I told it before: X-rays move very fast!)
* ablative compression of the tamper and fusion fuel: 200-500 ns.
(you say it is impossible to contain X-rays for 100 ns)
* fusion burn: 20 ns.

It can be done. It *has been* done.

Compared to the above, our task doesn't even require X-rays to be contained for hundreds of nanoseconds. It appears the shape-forming casing needs to survive for only 10 ns or so.

 

[Morbius]

Okay. The numbers for fusion device I learned from public sources:

* generation of X-rays in 1st (fission) stage: ~50 nanoseconds.
* arrival of X-rays, thermalization of tamper and casing surface: 10 ns.
(As I told it before: X-rays move very fast!)
* ablative compression of the tamper and fusion fuel: 200-500 ns.
(you say it is impossible to contain X-rays for 100 ns)
* fusion burn: 20 ns.

It can be done. It *has been* done.

Compared to the above, our task doesn't even require X-rays to be contained for hundreds of nanoseconds. It appears the shape-forming casing needs to survive for only 10 ns or so.

nikkom,

In ICF, the fusion fuel is compressed by the X-rays from the laser drive.

Is the time it takes the fuel to move so that it is compressed necesarily equal to the time that the drive acts on the fuel?

Suppose I am playing baseball, and it takes 20 seconds for the ball that I hit to travel from home plate where I hit it, out to the left field foul post where it strikes the post. From that information, can we then conclude that the bat was in contact with the ball for 20 seconds when it got hit.
( Suppose I'm saying that it is impossible for the bat to maintain contact with the ball for 10 seconds )

That is EXACTLY the assumption you've made above when you compare compression times to the time that radiation is contained.

Gregory

 

[puncheex]

In the early 60s, before the PTBT went into effect, the Soviets did a number of such tests; they were wild about throwing their primitive missiles of the time up in trajectories of thousands of miles across their own territory, ending in nuclear blasts above Kazakhstan and Novaya Zemlya. The chief object was developing anti-missile technology. No other country (US included) ever played that loose. Only one time did the Soviets mess up - the test known as K-3 didn't make it to its intended target but exploded high over central Kazakhstan, and caused widespread EMP damage on the ground, reportedly burning down a power generation station.