NIF

hype. What counts is the energy: 1.85 megajoules.

Gasoline is about 35 MJ/L, so that's 1.85/35 = 5.28e-2l, or about 52.8ml.

"

NIF is often described as a promising new source of energy. That is very unlikely to happen.

Regards,

Mike

Is that like "passing gas" ?:-) ...Jim Thompson

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

Well, it's rather trivial to get more than 1.85 MJ from a shot of fusion, for any macroscopic quantity of material. The equivalent volume of gasoline has no bearing on overall system efficiency.

Try a well reasoned criticism instead.

Tim

-- Deep Friar: a very philos>

Something's not right, where did the rest of the 500TW go?

1.85MJ out is an awful efficiency, unless that was *per* LASER (192 of them = 355.2MJ ~= 11L of petrol), but still many orders of magnitude less energy out than was put in?

Chris.

"Chris

Energy = 1.85 exp 6 joules

Pulse duration = 3.7 exp -9 seconds

... Phil

Assuming evenly distributed energy, isn't it along the lines of:

P = 500TW = 500TJ/sec E = 1.85MJ

t = 1.85MJ / 500TW = 3.7nS

"Dennis"

.... Phil

ZZZzapety-doo-da. Very precise zappety-doo-da.

Read it again then, dufus.

Mmm, your post wasn't among the headers when I posted. So I guess given the time stamps I'm backing your answer!

Read article. Very narrow pulse.

Yes, the efficiency is extremely low. That's why it will never become a usable energy source. It's only good for studying the secondary explosion in a hydrogen bomb.

The primary explosion is fission from plutonium. This provides the energy needed for the secondary, which is fusion. But treaties prohibit testing with actual bombs, so they use supercomputers to model the process. Some parts of the process are not very well understood, so they need to do actual experiments. That's the purpose for nif. The explosions are tiny and do not release any radiation, so they do not qualify as actual hydrogen bombs.

But selling it as a possible future energy source is just a scam. They know it can never be turned into a fusion reactor.

Regards,

Mike

The fusion energy released pershot is about equal to the caloric value of one jelly donut.

The entire shot is around 30 ns, and most of the energy is near the end.

It's the biggest laser in the world, and I was wondering if it was the biggest electronic gadget. Probably not. CERN probably has more electronics, and a Google data center even more.

_trillion_watts/

very

Interesting technology. I am particularly impressed with the conversion efficiency from infrared to ultraviolet. But the efficiency from the flash pump is horrible. Quote:

"of the 422 MJ pumped into the capacitors, only 1.8 MJ makes it into the reactor chamber."

So to reach breakeven, they would need to generate more than 422MJ on each shot.

There are other problems with cooling the lasers and finding ways to prevent radiation damage to the enclosure. These put breakeven out of reach with their approach, even though they promote the hell out of use as a fusion rector for power generation. For example, see

They do talk about weapons research:

But if they were really interested in commercial power plants, they would have engineers looking at ways to prevent radiation damage to the shell, and looking at ways to cool the lasers to provide continuous operation. They don't talk about these kinds of problems, and there seems to be no effort to working on them besides posting web pages that discuss pie-in- the-sky dreams. So it is clear the only real reason for nif is weapons research, and to train newcomers to atomic weapons.

Which is fine. I'd much rather they do that than play with actual hydrogen bomb explosions.

Regards,

Mike

;)

It's harder doing it twice with the same apparatus, though.

Cheers

Phil Hobbs

gasoline

For anyone who hasn't seen this, it's a great period piece, both for the physics interest and the 1950s movie style:

Cheers

Phil Hobbs

Cheers

Phil Hobbs

Well, the other inertial confinement machine, the Z machine, really had a problem, that would release a 32 megaAmp pulse into a "hohlraum" made of gold foil with copper contacts. It must have blown the contacts, etc. to bits, as they only did a couple shots a YEAR with that machine. But, I gather that gave them significant data to work with.

The NIF has a huge evacuated sphere with windows for the laser beams to shine in through. It is supposed to handle many pulses/day.

Jon