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Old 17-06-2009, 10:52 PM
tornado33
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Join Date: Jan 2005
Location: Newcastle, NSW, Australia
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I think they are barking up the wrong tree anyway. Rather than trying to heat up the fuel to millions of degrees, then try and confine it enough to fuse, then try and get a net energy gain,colliding beam aneutronic fusion might be the go

Quote:
Another approach to nuclear fusion–an approach that could lead to aneutronic power (power without neutrons) and non-radioactive nuclear energy–uses the concept of colliding-beam fusion (CBF). One aneutronic method features the 2H + 3He reaction leading to the products 1H + 4He. However, this requires 3He as fuel and terrestrial sources of this are limited. The Moon is a potential source of 3He produced by cosmic-ray protons hitting the Moon directly and not being absorbed by an atmosphere as on Earth. Another potential approach for colliding beam fusion is the 11B + 1H reaction leading to the three 4He nuclei. The energy release is in the form of charged particles whose kinetic energy can be converted to electricity with a very high efficiency. Current research predicts that this energy source has an extremely high degree of cleanness and efficiency. In all current energy sources, approximately two-thirds of the energy is lost in the form of waste heat or thermal pollution. In the CBF approach, there is virtually no waste. This design favors small size for the greatest efficiency (100 MWe or less), and would lead to either power plants with several reactors or decentralization of energy production.
This article too
Quote:
Migma fusion
The Migma approach avoided the problem of heating the mass of fuel to these temperatures by accelerating the ions directly in a particle accelerator. Accelerators capable of 100 keV are fairly simple to build, although in order to make up for various losses the energy provided is generally higher. Later Migma testbed devices used accelerators of about 1 MeV,[2] fairly small compared to the large research reactors like Tevatron, which are a million times more powerful.

The original Migma concept used two small accelerators arranged in a collider arrangement, but this reaction proved to have fairly low cross-sections and most of the particles exited the experimental chamber without colliding. Maglich's concept modified the arrangement to include a powerful magnetic confinement system in the target area; ions injected into the center would orbit around the center for some time, thereby greatly increasing the chance that any given particle would undergo a collision given a long enough confinement time. It was not obvious that this approach could work, as positively charged ions would all orbit the magnetic field in the same direction. However, Maglich showed that it was nevertheless possible to produce self-intersecting orbital paths in such a system, and he was able to point to experimental results from the intersecting beams at CERN to back up the proposal with real-world numbers.

Several Migma experimental devices were built in the 1970s; the original in 1972, Migma II in 1975, Migma III in 1978, and eventually culminating with the Migma IV in 1982. These devices were relatively small, only a few meters long along the accelerator beamline with a disk-shaped target chamber about 2 m in diameter and 1 m "thick". This device achieved the record fusion triple product (density × energy-confinement-time × mean energy) of 4e14 keV sec cm-3 in 1982, a record that was not approached by a conventional tokamak until JET achieved 3e14 keV sec cm-3 in 1987.

Maglich has been attempting to secure funding for a follow-on version for some time now, unsuccessfully. According to an article in The Scientist, Maglich has been involved in an apparently acrimonious debate with the various funding agencies since the 1980s.


Migma drawbacks
One more recent concern with the Migma design is that the particles lose energy through collisions with other particles in the reaction area, and through other interactions that only become an issue at very high energies, notably bremsstrahlung. These processes remove energy from the "fast" particles being injected, lowering their temperature and feeding it into the surrounding fuel mass. It appears there is no obvious way to "fix" this problem.[3] Whether this concern applies to the Migma is not clear
They should fund more of these experiments. A lot cheaper. Easier to acellerate particles to a modest 100 kev than folling around with the massive ITER

Note its possible to directly convert the fusion to electricity, no boiling water to make steam. If they could pull it off that means very cheap reliable power from a reactor with virtually no moving parts.
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