Heavy Ion Fusion Process Heavy ion accelerator drivers can provide the energetic ignition beams needed for Inertial Confinement Fusion (ICF) that are beyond the capabilities of laser technologies. These accelerator systems also possess the repetition rate, efficiency, and durability needed for power production. Fusion power is not a distant hope. It is at our doorstep. In fact, it could have been done a decade or more ago. The requirements for practical fusion power are known, but the ramifications of using known accelerator technology on the timeline to fruition are widely misinterpreted. National priorities in 1979, when the HIF ICF process was initially ready to be pursued, were not in favor of fusion, and consummation of this effort has been delayed until now - when priorities for a new energy source are paramount. A known technology with a known solution that can solve our greatest known problem - the lack of a viable future energy supply. In
the ICF approach known as Heavy Ion Fusion (HIF), beams of high-energy
heavy ions provide the energy to compress and ignite fusion fuel. The
processes are intense and brief; the fuel “burns” in the brief moment
before it dissipates—less than a billionth of a second .
Development of inertial confinement fusion (ICF) began in 1962, shortly
after the invention of the pulsed (Q-switched) ruby laser. In 1976, a
special workshop called by the US Energy Research and Development
Administration (now DOE) concluded that the technology of high energy
particle accelerators holds all the capabilities required for power
production using ICF. The engineering attributes of particle accelerators are essential for economic power production. In routine operation, accelerators convert electricity from the mains to beam energy with high efficiency; pulse (unless d.c.) many times per second; and last until supplanted by new accelerator technology. These attributes complete the picture for power plants, but more basic is the ability of heavy ions to provide ignition beams with the robustness needed to achieve ignition with confidence. Fuel compression is the key to scaling fusion explosions down. When the fusion burn starts in fuel that has
been compressed to high density, the fusion reactions heat the fuel to
still higher temperature, which accelerates the reaction rate. The
surrounding fuel ignites in a “propagating burn”, resulting in the
fusion energy output being many times the input for ignition. ICF
research has demonstrated fuel compression to hundreds of times the
density of solid hydrogen isotopes.  The degree of compression already demonstrated in ICF research is sufficient for Heavy Ion Fusion using the FPC driver. This is because HIF will employ the process known as fast ignition, the benefits of which are shown in the figure above. Representing the results of fifty years of intensely exploring the limits of compression, the curve labeled "Fast ignition (laser)" illustrates the boost that the National Ignition Facility would get if a laser could achieve fast ignition. The obstacle to laser-driven fast ignition is the inability of laser light to penetrate matter at normal solid density. In contrast, heavy ion beams penetrate solid matter according to physics that has been in standard practice for three-quarters of a century. A
decisive factor is the physics of how the beam energy couples into the
fuel target. The figure above shows the large increase in the ratio
of energy out to energy in (“gain”) that results from separating the
process of fuel compression from that of ignition. This process called “fast ignition”
is analogous to using a blasting cap to ignite a stick of dynamite;
compressing the fuel renders it “explodable”, the “fast ignition” spark
sets it off. But the NIF “point design” in the figure shows that fast
ignition by laser is, as put by the leader of the NIF program, “futuristic”,
owing to the exquisite complexity of the physics proposed to get some
of the laser energy from its stopping point in “underdense” matter to
where it is needed in the compressed fuel. In stark contrast, heavy ions
can access the ideal location in the compressed fuel via the “classical
physics” known since Neils Bohr provided the formula in 1926. With
beams carrying the energy needed
for ignition, and having the ability to put the energy in the right
places in the target, and being created by technology having efficiency
and engineering robustness, HIF has the “right stuff” for fusion power. At
the time that President Reagan said: “Now, the same scientists that
brought us these terrible weapons will make them impotent and
obsolete.”, those same words could have been used to announce that the
US would defuse the tensions of the world by developing an abundant
source of affordable energy that was not prone to the inevitable
tensions arising from nature’s capricious placement of fossil fuel
resources. The figure below illustrates the essence of the challenge of power production from inertial confinement fusion (ICF). In real terms as well as qualitative, the essential requirement is to displace the use of a fission explosion to ignite a much smaller fusion explosion. The conventional process for miniaturization of any invention is to reduce the size in moderate steps. In the absence of a large driver, development of ICF has been dominated by scaling up laser technology. The blue shaded region illustrates the limitations of lasers.  When accelerators
demonstrated storage of megajoules of beam energy (approximately the
energy from a stick of dynamite) in 1975, and it was realized that
accelerating heavy ions instead of protons (hydrogen nuclei) would cause
such energy to deposit efficiency in ICF’s small targets, the
accelerator community came forward to join with their colleagues in the
ICF community to achieve fusion power in a joint effort. Fusion power is not a distant hope. It is currently a realizable technology, FPC's fusion technology can be applied today. It can, and will, solve our energy problem. Copyright (C) 2011. All Rights Reserved |
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