2008-12-26

General Fusion: Generating Nuclear Fusion

clipped from nextbigfuture.com
General Fusion is a venture capital funded company that is taking an acoustic wave approach to magnetized target fusion (MTF). The approach is to have a sphere surrounded by steam pistons that drive a pressure wave inward to generate fusion compressions twice every second. They have performed some actual proof of concept experiments at 25 times slower piston speed and performed full scale computer simulations.
clipped from www.popsci.com


This Machine Might* Save the World

Two desktop-printer engineers quit their jobs to search for the ultimate source of endless energy: nuclear fusion. Could this highly improbable enterprise actually succeed?

clipped from www.popsci.com

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The energy from all power sources (except nuclear fission and geothermal) ultimately comes from the sun. The sun itself produces its energy from a process called fusion.

Fusion Basics

Fusion is the process where two light nuclei collide and fuse to form a heavier nucleus. A large amount of energy is released in the process and the most suitable reaction occurs between the nuclei of two heavy forms (isotopes) of hydrogen; deuterium and tritium. After fusing, helium and a neutron are produced.

Magnetic Fusion

One of the approaches considered to achieve fusion is to trap the plasma in a magnetic field. The negative electrons and positive nuclei in the plasma will spin around magnetic lines but diffuse only slowly across them. The best magnetic machine loops the magnetic line into a doughnut shaped region. So the particles spiral along the field line, go around the doughnut and cannot easily escape. This arrangement is called a Tokamak.


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Inertial Confinement Fusion (ICF)

A different approach is to fill a small (~1 cm) spherical shell of plastic or glass with a deuterium-tritium gas mixture. Intense lasers are fired all around the sphere, exploding the outside of the shell. The rest of the shell is accelerated inwards by the pressure of this explosion and compresses and heats the gas mixture to fusing conditions. The inertia of the imploding material alone keeps the plasma together for a short time. Because the hot plasma exists for only a very short time, it must be very dense to produce enough fusion reactions to make more energy than the laser energy.



Laser energy
Blowoff
Inward transported thermal energy



Magnetized Target Fusion

MTF is a fusion approach that is in between magnetized fusion (MF) and inertial confinement (ICF).
clipped from wsx.lanl.gov
General Fusion

General Fusion is using the MTF approach but with a new, patented and cost effective compression system to collapse the plasma.

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clipped from www.popsci.com
1. The impact of the pistons sends a compression wave reverberating through the liquid metal and toward the the plasma suspended by a magnetic field in the center.
2. The compression wave picks up speed as it hurtles toward the center, quickly becoming a shock wave powerful enough to compress the plasma quickly and violently.
3. The shock wave hits the plasma, a highly energetic stew of the hydrogen isotopes tritium and deuterium. The force is so great that the ions merge to form helium.
4. The fusion reaction hurls neutrons and alpha particles out through the liquid lead-lithium, creating heat that generates steam to power an electricity-producing turbine.

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Related:
Next Big Future: Update on General Fusion : Steam Punk Approach to Nuclear Fusion
This Machine Might* Save the World | Popular Science
General Fusion
Generating nuclear fusion
More money for fusion energy | News Blog - CNET News