NASA Langley pB11 Fusion Scheme

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Giorgio
Posts: 3061
Joined: Wed Oct 07, 2009 6:15 pm
Location: China, Italy

Post by Giorgio »

Another article on the subject at NBF:

"Laser Particle Acceleration: Status and Perspectives for Nuclear Physics"
http://nextbigfuture.com/2011/07/laser- ... s-and.html

nextbigfuture
Posts: 43
Joined: Thu May 29, 2008 5:48 pm

Details of a multi-terawatt pulsed laser from 2007

Post by nextbigfuture »

http://nextbigfuture.com/2011/07/100-mh ... econd.html

We run routinely the 10-TW-class CPA Ti:sapphire laser system, and a 100-MHz femtosecond multi-terawatt laser pulse train including several pulses in per pumping period is obtained. The pulse interval of pulse train can be adjusted by variation of the cavity length of regenerative amplifier.

We have obtained the 100-MHz pulse train with 1-TW peak power per pulse in our 10-TW-class Ti:sapphire laser system. In conclusion, we have demonstrated a new approach to generate a femtosecond multi-terawatt pulse train at repetition rate of 100 MHz in a 10-Hz CPA Ti:sapphire laser system, which contains a regenerative amplifier with an electro-optic Q-switch. The method of producing high power laser pulse train at high repetition rate can be used to any CPA laser systems of single shot or 10-Hz repetition rate. Specially, with the pulse selector as a switch, the CPA Ti:sapphire laser system can produce a femtosecond multi-terawatt pulse train or single pulse at per pumping period. The availability of such laboratory scaled ultrafast terawatt lasers at high repetition rate promises to open the door to investigations into the new fields of physics and applications.

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It looks like all the specs for the Chapman laser can be met. I think the regenerative amplifier system has been applied to petawatt lasers

dkfenger
Posts: 30
Joined: Thu Jul 07, 2011 9:55 pm
Location: Victoria, BC

Post by dkfenger »

For anyone that was curious about this, nextbigfuture found John J. Chapman's full paper:
http://nextbigfuture.com/2011/09/advanc ... space.html

Still looks like it's mostly theoretical work, pointing out the potential without actually trying to build anything in the lab. Yet.

The interesting point from the paper, and one I'd not really fully understood before, is that even with an under-unity efficiency one can still get a very nice thruster out of it. The author claims an ISP of about 900,000.

That alone makes it interesting as a stepping-stone - even if it can't produce net power out, it is useful.

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