Plasma Fusion (Hot Fusion)
- 1 Background of technology, including the basic science foundation
- 2 Required inputs for energy generation
- 3 The current state of a technology
- 4 Organizations/researchers working with this technology
- 5 Reasons why the science and technology has not moved forward
- 6 Costs of facilities, production, now and projected future costs with improvements
- 7 Intellectual Property surrounding technology
- 8 Ability to be scaled
- 9 Environmental impact
- 10 Risks associated with a prize in this space
- 11 Positive energy tests to evaluate this technology
- 12 References
Background of technology, including the basic science foundation
Nuclear fusion power is based on fusing atomic nuclei together to create elements, or isotopes, that have a higher nuclear mass. [Note that this is a different process to that used in today's nuclear power stations: they use nuclear fission, which involves splitting nuclei up into lighter elements, or isotopes.]
Typically, after the fusion reaction, this results in a loss of total mass. This lost mass is converted into energy, in accordance with Einstein's famous equation E = mc2. The mass lost is represented by m, and the c is the speed of light. Given that the speed of light squared is a huge number, the conversion of just a small amount of mass into energy produces a lot of energy.
However, fusing nuclei together presents a significant challenge because of the electrostatic repulsion of the positively charged nuclei that force them apart. In the Sun this is achieved by the high temperatures and pressures at its core. Here on Earth, we have achieved nuclear fusion, of hydrogen isotopes, by the high temperatures of an initial fission explosion that triggers a Hydrogen bomb; or in the laboratory by heating plasma to very high temperatures. This is slowly showing signs of progress, and an international demonstrator project (ITER) is underway to show how this could be used to produce electricity. This is a large and expensive project, costing billions and spanning decades.
The following video provides a nice introduction to the subject of power from nuclear fusion: Is alluring but elusive fusion energy possible in our lifetime?
We can try to create our own nuclear fusion reactors on Earth, or we can make use of the largest fusion reactor in the solar system (the Sun). The utilisation of energy from the Sun is described in Solar Technologies.
What is plasma?
When gas is ionised that represents a plasma. Ionisation involves stripping one or more electrons from an atom. This results in free electrons and positively charged ions (atoms with missing electrons). Plasma can conduct an electrical current.
Examples of plasma conducting electricity can be seen when you look at a neon sign or a yellow (sodium) street light; or lightning.
The ionisation that creates a plasma can be caused by an electric current (as in the above lights) or by very high temperatures (as in the Sun).
Like any other electric current, an electric current in a plasma can be controlled, or displaced, by a magnetic field. This is fortunate because the high temperature plasmas used in nuclear fusion are so hot that they would melt the material of their container if they touched it. Using a clever combination of magnetic fields the plasma is kept away from the walls of the container.   The process is shown in How does a magnetic field confine a plasma? (video) 
You can read more about plasma in the following reference. 
Required inputs for energy generation
The inputs for any energy generation process can be represented as shown in the System Representation.  The efficiency of the system is represented by the output energy divided by the input energy. Note that all energy inputs should be accounted for. In this case the input energy consists of the potential nuclear energy of the resource to be consumed (e.g. deuterium and tritium) and an input energy to raise the temperature. To generate the high temperature plasma a significant amount of energy is input into the system to start the nuclear process off. A viable system will then become self-sustaining with heat from the fusion reaction maintaining the high plasma temperatures. Although some pellet based approaches might need repeated injections of this input energy to trigger the nuclear reaction for each pellet (though again, a viable system should generate much more energy than it requires to trigger reactions).
A significant disadvantage of high-energy fusion methods (as opposed to low-energy nuclear reactions, LENRs) is the amount of energy required to reach the conditions under which fusion actually occurs. This is directly related to the Coulomb repulsion of two positively charged nuclei. There are several ways to reach such high-energy conditions:
- Gravity: fusion in the stars initiates when sufficiently large molecular clouds undergo gravitational collapse, leading to the high temperatures and pressures required for hydrogen fusion (10 million Kelvin).
- Atomic bomb: in a so-called H-bomb, a nuclear fission reaction acts as a first stage to cause radiation implosion on a reservoir of hydrogen, which then fuses.
- Lasers: at facilities such as NIF, a series of laser beams is fired on a metal target, causing it to implode upon its content of hydrogen, creating the conditions for fusion. These lasers are of course powered by electricity. The peak power injected at NIF is 500 TW, or about 40x the entire world's average power use (but for a very short time-span).
- Heating: tokamaks such as ITER or JET use a combination of Ohmic heating, Neutral Beam heating and RF heating, which in turn require electricity. When JET runs, it consumes 700 – 800 MW of electrical power, which is the equivalent of 1-2% of the UK’s total electricity usage.
Extracting more energy from the fusion reaction than what was put in to get the reaction going, the so-called fusion energy gain factor Q, is an important parameter for fusion reactor design.
In his article "The selling of ITER", critic Steven Krivit highlights the need to clearly define which inputs/outputs are taken into account when calculating this fusion energy gain factor, and distinguishes between "scientific breakeven", "engineering breakeven" and two other forms of breakeven:
"To fully understand the special meaning of “fusion power,” we must understand some basic aspects of experimental fusion machines like ITER. Extreme temperatures — more than 100 million degrees Celsius — are necessary to create an environment in which atomic nuclei are forced closely enough together so they can bind and undergo nuclear fusion. Hydrogen isotopes (deuterium and tritium) are used as fuel in many fusion reactors. The reactor design concept comes from Russia, from an invention called a tokamak device. Inside the tokamak, heat is applied to the hydrogen isotopes and, when hot enough, the hydrogen forms a plasma. A plasma is like a gas but is in fact a fourth state of matter. An everyday example of a (normal temperature) plasma creates the glowing discharge in neon signs. In experimental tokamak reactors, heating is accomplished in a variety of ways that convert electricity from the grid into thermal power applied to the plasma.
In addition to heating, the plasma must be kept from touching the metal walls of the machine. No material on Earth can directly contain the hot plasma inside the reactor. If the plasma touched a reactor’s wall, it would instantly damage the reactor by vaporizing wall materials and terminate the reaction. The technological marvel of containing the super-hot plasma is accomplished by suspending the plasma in the center of the reactor by using a magnetic field. Older tokamak devices use conventional electromagnets. ITER’s design uses more efficient superconducting magnets that require less input power. In any case, the magnets surrounding the reactor are one of the largest power-consuming subsystems in tokamak reactors. Accounting for the input power for the various subsystems is crucial to understanding the dual meanings of the ambiguous phrase “fusion power.”
The current state of a technology
The principle of nuclear fusion has been proven, and man has managed to fuse hydrogen in atomic bombs and under controlled conditions in tokamaks such as JET.
In 2012 at NIF, during an experiment in late September, the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel - the first time this had been achieved at any fusion facility in the world.
Many prototype reactors are being built around the world (see below), but none today is running continuously whilst generating net power.
The billionaire backed Breakthrough Energy Coalition lists Fusion among their landscape:
"Net energy production from controlled nuclear fusion—the fusing of two atomic nuclei—has long been considered the Holy Grail of clean energy: if we can accomplish it, we can provide enough zero-carbon energy to power the whole world. However, the very significant science and technology challenges associated with achieving controlled fusion have prevented the demonstration of net energy production to date, in spite of more than 60 years of research in this field. If and when net energy production from fusion is achieved, making it cost-effective will remain a very significant challenge as well. However, innovative new approaches in recent years have given rise to a nuclear fusion technology renaissance of sorts that may hold promise to open the way to providing the world with cheap, reliable, emissions-free fusion energy for the first time."
Organizations/researchers working with this technology
The quest for controlled fusion is a planetary challenge uniting thousands of scientists around the world. The field can be roughly divided into
- Publicly funded labs / projects, including the largest scientific construction project on earth today : the International Thermonuclear Experimental Reactor (ITER)
- Private companies trying to achieve fusion in other, more compact ways
A good recent review of the "fusion race" was published in Scientific American late 2016, and can be found on-line on researchgate.
ITER ("The Way" in Latin) is one of the most ambitious energy projects in the world today.
In southern France, 35 nations are collaborating to build the world's largest tokamak, a magnetic fusion device that has been designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy based on the same principle that powers our Sun and stars. The experimental campaign that will be carried out at ITER is crucial to advancing fusion science and preparing the way for the fusion power plants of tomorrow.
ITER will be the first fusion device to produce net energy. ITER will be the first fusion device to maintain fusion for long periods of time. And ITER will be the first fusion device to test the integrated technologies, materials, and physics regimes necessary for the commercial production of fusion-based electricity.
Thousands of engineers and scientists have contributed to the design of ITER since the idea for an international joint experiment in fusion was first launched in 1985. The ITER Members—China, the European Union, India, Japan, Korea, Russia and the United States—are now engaged in a 35-year collaboration to build and operate the ITER experimental device, and together bring fusion to the point where a demonstration fusion reactor can be designed (a follow-up reactor called DEMO).
Other publicly funded labs
- Sandia National Laboratories Z-Machine Is one of the most amazing things to see in action. This can create very high temperatures and is used for research into nuclear fusion. Plasma is created in a series of bursts of energy. The trick then is to get as much energy as possible out of small, high-density plasma fusion targets before they expand and cool. This is what is known as inertial confinement fusion, and this is the main approach used at Z. Inertial confinement fusion’s target is a BB-sized fuel capsule placed inside a container about the size of a spool of thread. An enormous pulse of power is focused for a few nanoseconds on the fuel capsule containing a mixture of hydrogen isotopes (deuterium and tritium). The source of power is often a laser, or in the case of the Z machine, a Z pinch. Whatever the source, the intense burst of power causes the target to implode, compressing the material in it and heating it to temperatures near those at the center of the Sun. If the heat and pressure are intense enough, the conditions should ignite a fusion reaction. 
- The National Spherical Torus Experiment (NSTX) at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) is yielding research results that may open an attractive path towards developing fusion energy as an abundant, safe, affordable and environmentally sound means of generating electricity. The NSTX device is exploring a novel structure for the magnetic field used to contain the hot ionized gas, called “plasma”, needed to tap this source of energy. Future fusion power plants will contain plasmas consisting of a mixture of the hydrogen isotopes deuterium and tritium, which can undergo fusion reactions to produce helium, accompanied by a large release of energy, if a sufficient temperature and pressure can be maintained in the plasma using the insulation provided by a suitably shaped magnetic field.
- K-DEMO South Korea has embarked on the development of a preliminary concept design for a fusion power demonstration reactor in collaboration with the US Department of Energy's Princeton Plasma Physics Laboratory (PPPL) in New Jersey. The project is provisionally named K-DEMO (Korean Demonstration Fusion Power Plant), and its goal is to develop the design for a facility that could be completed in the 2030s in Daejeon, under the leadership of the country’s National Fusion Research Institute (NFRI).
- NIF The National Ignition Facility is a large laser-based inertial confinement fusion (ICF) research device, located at the Lawrence Livermore National Laboratory in Livermore, California. NIF uses lasers to heat and compress a small amount of hydrogen fuel to the point where nuclear fusion reactions take place. NIF's mission is to achieve fusion ignition with high energy gain, and to support nuclear weapon maintenance and design by studying the behavior of matter under the conditions found within nuclear weapons. NIF is the largest and most energetic ICF device built to date, and the largest laser in the world.
- HiPER the European High Power laser Energy Research facility, is dedicated to demonstrating laser driven fusion as a future energy source. The HiPER Project will drive the transition from scientific proof of principle to a demonstration power plant, capable of delivering electricity to the grid. While the primary mission of HiPER is energy, HiPER will also support a wide range of science research. It is unclear whether the project is still active.
- Wendelstein 7-X Wendelstein 7-X is the world’s largest fusion device of the stellarator type with modular superconducting coils which enable steady state plasma operation in order to explore the reactor relevance of this concept. Its objective is to investigate the suitability of this type for a power plant. It will test an optimised magnetic field for confining the plasma, which will be produced by a system of 50 non-planar and superconducting magnet coils, this being the technical core piece of the device. The main assembly of Wendelstein 7-X was concluded in 2014. Once all technical systems had been checked step by step the first plasma was produced on 10th December 2015.
- FRX-L at Los Alamos a plasma is first created at low density by transformer-coupling an electric current through a gas inside a quartz tube. External magnets confine fuel within the tube. Plasmas are electrically conducting, allowing a current to pass through them. This current, generates a magnetic field that interacts with the current. The plasma is arranged so that the fields and current stabilize within the plasma once it is set up, self-confining the plasma. FRX-L uses the field-reversed configuration for this purpose. Since the temperature and confinement time is 100x lower than in MCF, the confinement is relatively easy to arrange and does not need the complex and expensive superconducting magnets used in most modern MCF experiments.
- LDX is a novel experimental device designed to explore the physics of plasma confinement in a magnetic dipole field. They have conducted the first experimental test on the theory of plasma confinement by adiabatic compressibility. Since the dipole field resembles the field of a planetary magnetosphere they can develop and test models of space weather using two state-of-the-art laboratory experiments, LDX at MIT and and CTX at Columbia. LDX is a collaboration between Columbia University's Dept. of Applied Physics and the MIT Plasma Science & Fusion Center and is funded by the NSF/DOE Partnership in Basic Plasma Science and Engineering.
- MagLIF Sandia and the Laboratory for Laser Energetics (LLE) at the University of Rochester will investigate the compression and heating of high energy-density, magnetized plasmas at fusion-relevant magneto-inertial confinement fusion (MIF) conditions, building on the recent Magnetized Liner Inertial Fusion (MagLIF) concept successes. The SNL-LLE team will conduct focused experiments based on the MagLIF approach at both SNL and LLE facilities, targeting key physics challenges in the intermediate plasma density regime. The team will also exploit and enhance a suite of simulation and numerical design tools validated by these experiments. Through this project, the team will provide critical information for improved compression and heating performance as well as insights on loss mechanisms and instabilities for hot, dense, magnetized plasmas.
- Alcator C-Mod at the MIT Plasma Science and Fusion Center began operation in 1993. C-Mod is a compact, high magnetic field, diverted tokamak. C-Mod has produced dense plasmas at greater than 100 million degrees, and holds the record for highest volume average plasma pressure in a magnetic confinement device. The MIT group is now developing a design for a next generation tokamak reactor utilizing high magnetic fields provided by HTS magnets built from REBCO tape. The conceptual design for a net energy power plant based on the new reactor is called ARC for Affordable, Robust and Compact. This design would produce about the same power as ITER, at much smaller size, for less cost and construction time. The team have also considered just how small a reactor could be built with the ARC reactor design and still surpass breakeven energy conditions. They are developing a university scale experimental design called SPARC, for Smallest Possible ARC reactor.
- SLAC National Excellerator Labratory - FACET's unique electron and positron beams provide a broad range of science opportunities from advanced accelerator R&D to materials science research. FACET is the only facility in world with the high intensity drive bunches necessary for high-gradient plasma and dielectric wakefield acceleration. Our infrastructure includes high brightness terahertz (THz) sources, a 20 TW laser and multi-purpose vacuum chambers.
General Fusion was founded in 2002 with a goal to transform the world’s energy supply by developing the fastest, most practical, and cost-competitive path to commercial fusion power. In 2006, Dr. Laberge completed proof-of-principle experiments, and with the support of leading venture capital firms, General Fusion began building a team that today is recognized as a global leader in commercial fusion energy. The company has now grown to a team of nearly 50 scientists at its world class laboratories in Burnaby, just outside Vancouver, where it is developing the key components of the world’s first fusion power plant.
General Fusion has been recognized globally for its work in clean energy technology, and is a member of the Cleantech Global 100 (2014, 2015) as well as the recipient of numerous Canadian and international cleantech awards. In the media, Dr. Laberge’s 2014 TED Talk about fusion energy has attracted over one million viewers, and the company has been featured in publications such as TIME Magazine, Scientific American and BBC Horizons.
Fusion energy has the potential to create a cleaner, safer world, and General Fusion is developing the technology to make it available as soon as possible.
Tri Alpha Energy
Tri Alpha Energy is the world’s largest private fusion company. Its purpose is to deliver world-changing clean fusion energy technology as fast as possible. Starting with the end in mind, a commercially competitive fusion power plant, the company developed a unique combination of well-understood advanced particle accelerator and plasma physics. The resulting technology is compact, aneutronic, safe, carbon-free and sustainable.
Backed by $500 million in private capital from some of the world’s leading energy and technology investors, the company is well along in validating both the science and engineering integration of this technology. The company’s “money by milestone” venture capital mindset and fast cycle learning capability have driven disciplined, steady progress. While important work remains, Tri Alpha Energy claims to understand the path forward to the first fusion-based commercial power plant.
Tri Alpha Energy technology applies a fundamentally different approach to addressing the historic challenges that have hampered fusion-based electricity generation – the inability to maintain fuel particles (plasma) “long enough” and at temperatures “hot enough” to validate the path to fusion power.
Compact Fusion (Lockheed Martin)
The Lockheed Martin Compact fusion reactor is a project being developed by the company's Skunk Works division. The project aims to "build and test a compact fusion reactor in less than a year with a prototype to follow within five years." The prototype would be a 100-megawatt deuterium and tritium reactor measuring seven feet by 10 feet that could fit on the back of a large truck and be about 10 times smaller than current reactor prototypes.
Focus Fusion (Lawrenceville Plasma Physics)
LPPFusion is a high tech R&D company centered on the development of a new environmentally safe, clean, cheap and unlimited energy source based on aneutronic fuels and the dense plasma focus device, a combination they call Focus Fusion.
LPPFusion’s nuclear fusion R&D project was initially funded by NASA’s Jet Propulsion Laboratory and is now backed by over eighty private investors. LPPFusion’s patented technology and peer-reviewed science are guiding the design of this virtually unlimited source of environmentally clean energy that can be significantly cheaper than any other energy sources currently in use. They are working to demonstrate the scientific feasibility of Focus Fusion at their laboratory in Middlesex, NJ.
One of the most well known scientists involved in this project is Eric J Lerner, author of the 1991 book The Big Bang Never Happened, which advocates Hannes Alfvén's plasma cosmology instead of the Big Bang theory.
By combining years of experience in fusion, newly available electronics technologies, and a revolutionary design using cutting-edge physics, Helion is making a fusion engine 1,000 times smaller, over 500 times cheaper, and realizable 10 time faster than other projects. The Helion team has designed and built award-winning technology and fusion prototypes many experts in the field consider the most promising approach to commercial fusion. Helion Energy is backed by a world-class team of American investors, technical advisors from throughout the fusion community, and the Department of Energy.
HyperV Technologies Corp. is a privately held fusion energy research and development company founded by Dr. F. Douglas Witherspoon in 2004 and located in Chantilly, Virginia U.S.A. The company specializes in the development of unique ultra-high performance plasma guns for use in fusion energy, plasma physics research, and industrial applications. The name HyperV comes from the word “HyperVelocity” and references the extremely high velocities achieved by plasma when formed and fired from our plasma guns.
Since its establishment in 2004, HyperV Technologies Corp. has received funding through a series of research grants from the U.S. Department of Energy’s Office of Fusion Energy Sciences (OFES). HyperV was awarded these grants and numerous SBIR’s, following a highly competitive proposal and rigorous scientific peer review process.
In continuing the advancement of it’s most promising fusion energy research and development effort, HyperV has teamed with the legendary Los Alamos National Laboratory (LANL) of New Mexico. This HyperV/LANL partnership is focusing on the design, development and operation of the PLX-α experiment located at LANL in New Mexico and funded by the DOE Advanced Research Projects Agency-Energy. In this design, hundreds of guns fire bursts of argon plasmas into the center of a spherical reactor, where they converge and compress hydrogen fuel.
Magneto-Inertial Fusion Technologies, Inc. (MIFTI)
MIFTI was founded in 2008 by scientists from the University of California Irvine. For over 25 years, these scientist have researched and refined a method of controlled thermonuclear fusion, based on Staged Z-Pinch. This concept has predicted a net gain of controlled thermonuclear fusion energy that can possibly solve the world's energy problems. A by-product of this fusion reaction can also be used to generate radioisotpes that are used in nuclear medicine procedures worldwide.
MIFTI’s technology will have positive worldwide consequences, not only for energy, but will solve the current crisis of worldwide shortages in nuclear medicine, as staged Z-pinch is very flexible and can be applied to a number of earth’s dilemmas. MIFTI’s goal is simply to provide the people of earth with energy and medicines, at a reasonable and fair price, with no carbon dioxide emissions. MIFTI technology is environmentally friendly – and forever.
Tokamak Energy Ltd
Tokamak Energy aims to accelerate the development of fusion energy by combining two emerging technologies – spherical tokamaks and high-temperature superconductors.Tokamaks are the most advanced fusion concept in the world, but we take an innovative approach to develop fusion faster. Our business model is based on agility and “open innovation” – working collaboratively with universities, research laboratories and businesses whilst ensuring that we retain the ownership of crucial intellectual property.
Reasons why the science and technology has not moved forward
The science of plasma fusion has moved forward significantly, what remains to be conquered is an (extreme) engineering challenge.
While fusion sounds simple, the heating, compressing and confining hydrogen plasmas at 100 million degrees is a significant challenge. It has taken a lot of science and engineering research to get fusion developments to where they are today. Following the first fusion experiments in the 1930s, fusion physics laboratories were established around the world. By the mid-1950s “fusion machines” were operating in the Soviet Union, the United Kingdom, the United States, France, Germany and Japan.
The Wendelstein 7-X and EAST reactor experiments were dubbed “breakthroughs,” which is an adjective commonly applied to fusion experiments. Exciting as these examples may be, when considered within the scale of the problem, they are only baby steps. It is clear that it will take more than one, or a dozen, such “breakthroughs” to achieve fusion.
Ultimately, the question may be one of funding. Multiple scientists have said they were confident that their research could progress faster if they received more support. Funding challenges certainly aren’t new in scientific research, but nuclear fusion is particularly difficult due to its near-generational timescale.
Scientists believe the commercial availability of REBCO superconducting tape, suitable for building superconducting magnets which retain superconductivity in very high magnetic fields, opens new opportunities to build tokamak fusion reactor designs capable of getting closer to and ultimately achieving breakeven energy gain at much smaller reactor sizes than traditionally expected.
ITER is expected to start operating in the 2020s, but after that another prototype is required to demonstration electricity generation. "Electricity generation is expected in 30 to 40 years" [around 2042 to 2052, given 2012 publication date for article]. 
The current thinking in Particle Physics
The current thinking in Particle Physics may be in error leading to miscalculations.
In his book The Higgs Fake, Alexander Unzicker makes the following points:
1) The so-called standard model has grown unbelievably complicated,
2) None of the great riddles of physics that have persisted for a century have been solved,
3) History suggests that the current model is a dead end,
4) With their ever-more intricate experimental techniques, particle physicists are fooling themselves with alleged results,
5) Scientific convictions in the community are established by trust in expert opinions, group-think and parroting, and
6) The data analysis in its complexity cannot be overseen by anybody.
Unzicker backs his claims with a short historical survey and concludes that particle physics, as practiced since 1930, is "a futile enterprise in its entirety." In the last section of his book, "Antidotes," he specifically attacks "the overstated claims by famous physicists. He continues "There seems to be no chance for physics to get rid of unsuccessful theories once they have settled down and lodged in a comfortable environment."
Conversely, the physicists at CERN, the world's largest particle accelerator conducting multiple particle physics experiments, might dispute the contents of the above book: In Theory: Is theoretical physics in crisis?
The science is proven, it is now an (extreme) engineering challenge.
Natural Philosophy Society
The John Chappell Natural Philosophy Society serves as a networking center for the 4,000 or more known scientists that have issues with the accepted foundations of science. Their whiteboard video on The Higgs Fake - A Critique of Modern Particle Physics can be seen here: https://www.youtube.com/watch?v=uy5nMXK9s4k Herein lies the crux of the issue; iis physics well enough understood to allow the successful fabrication of a hot fusion reactor?
A quick view of the Membership shows that the society has a limited number of scientists, many are not scientists, but engineers (and other roles); and some of the science topics are dubious - for example, the first one "aether" is not part of modern day physics.
Costs of facilities, production, now and projected future costs with improvements
Cost and timeline are critical parameters for fusion energy, because of the relatively complex installations required. With a very high starting point (in excess of 10 US$bln for ITER) far in the future, some question whether the cost-curve for fusion power will ever catch up with the cost curve for solar PV. The alternative concepts promoted by the start-ups all aim for much lower starting points on that cost-curve, and hope to get there sooner.
Intellectual Property surrounding technology
- US 20060198483 A1 Magnetized plasma fusion reactor A fusion reactor apparatus for initiating a fusion reaction in a fusionable material is disclosed. The apparatus includes a vessel operable to contain a liquid medium and a vortex generator operable to generate a vortex in the liquid medium. The apparatus also includes a plasma generator operable to generate a magnetized plasma of the fusionable material and to introduce the magnetized plasma into the vortex and a pressure wave generator operably configured to cause a pressure wavefront in the liquid medium to envelope the magnetized plasma and to converge on the magnetized plasma to impart sufficient energy to the fusionable material to initiate fusion in the fusionable material.
- WO 1997049274 A2 A method for generating nuclear fusion through high pressure A method of generating nuclear fusion, whereby bubbles of a gas of about 10 micron diameter, contained in heavy water, are expanded by use of a vacuum to about 100 microns in diameter. The subsequent thermal cooling and collapse of the bubbles is augmented by a uniform pressure externally applied and acting on the bubbles through the heavy water. Symmetry in the bubbles' shape is imparted by the addition of heat from a laser as the bubbles continue to contract. High pressures and therefore temperatures are achieved, sufficient to generate nuclear fusion in specific materials.
- WO 2003077260 A3 Apparatus and method for fusion reactor A method for inducing nuclear fusion and a reactor for inducing nuclear fusion involve positioning a bubble containing fusionable nuclei at the center of a liquid filled spherical vessel and generating a spherically symmetric positive acoustic pulse in the liquid. The acoustic pulse surrounds and converges toward the center of the vessel to compress the bubble, thereby providing energy to and inducing nuclear fusion of the atomic nuclei.
- US 3925990 A Shock heated, wall confined fusion power system A fusion-engine-reactor system having a shock heated plasma confined between two coaxial cylinders connected at one end by a concave shaped wall, a magnetic piston compresses the plasma and initiates the plasma fusion reaction, while a supplementary "stuffing" magnet confines the reaction to the end of the cavity, a lithium blanket and heat exchanger provide a means for converting the generated heat into usable energy to operate an attached turbine-generator assembly.
- US 9036765 B2 Method and system for inertial confinement fusion reactions Disclosed is a system for extracting energy from inertial confinement fusion reactions, which includes a central target chamber for receiving fusion target material. A plurality of energy drivers are arranged around the target chamber so as to supply energy to fusion target material in the chamber to initiate an inertial confinement fusion reaction of the material, releasing energy in the forms of fusion plasma and heat. A plurality of structures for extracting energy from the fusion reaction are provided, and comprise devices to extract high voltage DC energy from the fusion plasma, and means to extract thermal energy from the central target chamber. Power to the energy drivers may be supplied from high voltage DC energy extracted from the fusion reactions. The energy drivers may use an apodizing filter to impart a desired shape to the wavefront of the driving energy for causing the fusion reactions, to avoid hydrodynamic instabilities.
- US 9406405 B2 Fusion energy device with internal ion source An improved fusion reactor design with provision for supplying plasma fuel inside a model reactor without consuming additional power in the process. Embodiments provide free choice of useful fuels from the full range of fusible isotopes. Other embodiments provide means of selectively extracting up-scattered electrons from the plasma, followed by replacing them with electrons of corrected energy. Computer simulations show fusion reactors constructed with these inventive improvements will demonstrate increased net-power compared to other fusion reactors of similar size. The Specification of the invention leads immediately to staged reactor development, starting from small-scale model-reactors, moving on to larger and larger scale models, culminating with commercial power plants.
- US 4446096 A High speed plasma focus fusion reactor An electrical discharge thermonuclear reactor having a capacitor which is discharged into a reaction chamber through a low inductance distribution circuit funneling discharge current to a focus point in the reaction chamber so that the magnitude of the magnetic field intensity associated with the discharge current is generally inversely proportional to the square of the distance from the focus point. Then the circuit inductance is limited to a minimum value regardless of the absolute maximum distance from the capacitor to the focus point and thus the size of the capacitor. The distribution circuit has two outward-branching, interpenetrating three dimensional circuit networks of opposite polarity conveniently fabricated by stacking conductor plates having a generally cylindrical geometry. The distribution circuit spherically surrounds the reaction chamber so far as is practical so that the discharge rate, power and energy transfer to the reaction chamber are maximized and thus reducing the required size of the reactor.
- US 6654433 B1 Method and machine for producing energy by nuclear fusion reactions An experimental machine for producing low-temperature nuclear fusion reactions, wherein an ion source feeds a flux of positive deuterium ions to a reaction chamber housing a target defined by active elements and by an aggregate of metal sulfate hydrated with heavy water; a pumping assembly being provided to maintain a vacuum in the reaction chamber; and the reaction chamber having an accelerating device for accelerating the positive deuterium ions, and which generates an electric field inside the reaction chamber to convey and accelerate the deuterium ions against the active element of the target in such a manner as to initiate nuclear fusion reactions between the incident deuterium ions and some of the atoms of the active element.
- US 4182650 A Pulsed nuclear fusion reactor This invention relates to a nuclear fusion power plant for producing useful electrical energy by nuclear combustion of deuterium and lithium to helium. A large concentric plate capacitor is discharged rapidly through a mass of molten LiD1-x Tx (O<X<1) that is situated at its center. Before this discharge, a conducting path had been thermally preformed between the electrodes by an ac current pulse. The high-temperature, high-pressure plasma is confined by the LiD liquid in a narrow channel. Neutrons are generated, partly by thermonuclear fusion, partly by suprathermal collisions which result from the well-known sausage instability. Short n-6 Li-D-T chain reactions, enhanced by the beryllium content of the electrodes, are also present. The escaping neutrons are absorbed by the surrounding liquid where they breed T, which is then chemically bound, and produce heat. The heat, radiation and mechanical shock are absorbed in the liquid which flows through a heat exchanger in order to energize the associated turbogenerator power plant. After each pulse, the discharge channel vanishes and is homogenized in the liquid. This reactor cannot become supercritical, and does not produce radioactive waste.
- US 7482607 B2 Method and apparatus for producing x-rays, ion beams and nuclear fusion energy The present invention includes an apparatus and method for producing x-rays, and/or ion beams and for enabling the generation of fusion energy and the conversion of the energy into electrical energy including an anode and a cathode positioned coaxially and at least partially within a reaction chamber that imparts an angular momentum to a plasmoid. The angular momentum may be imparted through the cathode having a helical twist; a helical coil about the cathode or a combination thereof. The anode has an anode radius and the cathode has a cathode radius that imparts a high magnetic field. The reaction chamber contains a gas and an electronic discharge source in electrical communication with the anode and the cathode. As a result of an electronic discharge a dense, magnetically confined, plasmoid is created about the anode and emits of one or more particles.
- US 3386883 AMethod and apparatus for producing nuclear-fusion reactions "The present invention relates to a method and apparatus for producing nuclear-fusion reactions, and more particularly to a method and apparatus for producing controlled nuclear-fusion reactions by use of self-generated electric fields and inertial ionized gas containment."
- WO 2016070126 A1 Systems and methods for forming and maintaining a high performance frc A high performance field reversed configuration (FRC) system includes a central confinement vessel, two diametrically opposed reversed-field-theta-pinch formation sections coupled to the vessel, and two divertor chambers coupled to the formation sections. A magnetic system includes quasi-dc coils axially positioned along the FRC system components, quasi-dc mirror coils between the confinement chamber and the formation sections, and mirror plugs between the formation sections and the divertors. The formation sections include modular pulsed power formation systems enabling static and dynamic formation and acceleration of the FRCs...
- WO 2015163970 A3 Advanced fuel cycle and fusion reactors utilizing the same Examples of advanced fuel cycles for fusion reactors are described. Examples include fuel cycles for use in field reverse configuration (FRC) plasma reactors. In some examples, reaction gases may be removed from a fusion reactor between pulses (e.g. plasmoid collisions). In some examples, a D-3He reaction is performed, with the 3He provided from decay of byproducts of previous reactions (e.g. tritium).
- WO 2013112221 A3 Apparatus, systems and methods for fusion based power generation and engine thrust generation Systems and methods establish a magnetically insulated fusion process. An exemplary embodiment establishes a Field Reversed Configuration (FRC) plasma, wherein the FRC plasma is a closed field, magnetically confined plasma; collapses a metal shell about the FRC plasma; and establishes a fusion reaction in response to collapsing the metal shell about the FRC plasma.
Ability to be scaled
The energy generation process can be represented as shown in the System Representation. For this technology to be scaled up consideration needs to be given to the logistics of scaling up of the input energy and/or input materials, and to the environmental impact arising from pollutants, waste, and land use.
- Assuming deuterium is a key resource for this technology, the implications of large scale plants to extract this isotope (probably from sea water) would need to be assessed (e.g. costs and environmental impact).
- The potential impact of radioactive waste [particularly during decommissioning] should be investigated in greater detail.
It is only when all of these potential costs are estimated and totalled that we can determine the ability of this technology to be scaled. It requires an evaluation of its full socio-economic and environmental impacts.
There is little doubt that, once successful, fusion reactors can be scaled up and run almost indefinitely. This is the main reason why fusion is often labelled the "holy grail" of energy technologies. The fuels used by most concepts are sufficiently available or can be made on demand (Hydrogen from (heavy) seawater, Tritium from Lithium in a nuclear reactor).
Deuterium from seawater is a simple and well proven industrial process, according to the ITER article: Deuterium: a precious gift from the Big Bang. It also mentions how tritium is required to give a better reaction rate; and that it is slightly radioactive.
If it turns out that only large scale fusion plants (like ITER) are technically feasible then the ability to scale this approach might be limited by costs and construction times. There might also be questions about its suitability for the developing world. Alternatively, if small reactors (like Lockheed Martin) are feasible then costs and construction times might be less of an issue.
The long-term environmental impact of a prospective energy technology should be considered and compared with alternative technologies. One way to do this is to use a Sustainability Scale  This takes into account all aspects of the technology's life-cycle, including its dependencies. Although the sustainability of a nuclear fusion process might appear promising in terms of the long-term supply of deuterium, its environmental impact could have a significant factor in the form of radiation and radioactive waste associated with the decommissioning process.
The fuel consumption of a fusion power station will be extremely low. A 1 GW fusion plant will need about 100 Kg of deuterium and 3 tons of natural lithium to operate for a whole year, generating about 7 billion kWh, with no greenhouse gas or other polluting emissions. To generate the same energy, a coal-fired power plant (without carbon sequestration) requires about 1.5 million tons of fuel and produces about 4-5 million tons of CO2.
The neutrons generated by the fusion reaction cause radioactivity in the materials surrounding the reaction – such as the walls of the container etc. A careful choice of the materials for these components will allow them to be released from regulatory control and possibly recycled about 100 years after the power plant stops operating. Waste from fusion plants will not be a burden for future generations.
However, the above statement could potentially be misleading. Neutron bombardment affects the vessel containing the nuclear reaction, and so once the plant is decommissioned the site will be radioactive. The radioactive products are "short lived" (up to 100 years) compared to the waste from a fission power plant (which lasts for thousands of years). 
Risks associated with a prize in this space
Risks are associated with all radical innovations, and that can be due to several factors. A good technology might not succeed in the marketplace due to poor marketing and promotion. The perceived safety and environmental impact of a technology is also important to successful adoption.    The perception of the risks associated with a nuclear process are real and significant. Some people will inevitably confuse nuclear fusion and fission, and attribute the safety and environmental risks of current day fission reactors with those of the proposed fusion reactors. [In the early days of MRI scanners they were renamed from Nuclear Magnetic Resonance scanners to Magnetic Resonance Imaging scanners; perhaps to prevent [unwarranted] associations with nuclear fission.]
Poor implementation of a technology can also prevent successful adoption of a good technology. These are risks that come into effect after the awarding of an energy technology prize, but perhaps the associated challenge can provide post award support to ensure that these risks are reduced. In addition, of course, there can be risks associated with the technical efficacy of the technology itself, and the logistics surrounding its development, operation and decommissioning. The ITER project has shown that the construction of fusion energy plants can be expensive and slow; this might represent a risk in terms of trying to quickly solve the world's energy problems.
This fusion approach promises great potential: nuclear fusion could offer large amounts of energy. The risk of this approach is lowered by the key fact that the theory has been scientifically proven, by different researchers. We know that hydrogen isotopes (deuterium and tritium) can be fused in the laboratory, and that it results in a large release of energy (given the amount of mass).
So far though, this has only been demonstrated for short periods. A sustainable fusion reactor (with fuel input, spent material extraction, resistance to neutron bombardment, and energy capture) faces some formidable engineering challenges.
What we do not yet know is the:
- complete details of a sustainable fusion reactor
- actual net output of energy, and
- environmental and other implications of the full process life-cycle.
Projects are underway to develop prototypes that can sustain the fusion process and extract energy; but the timescales for these could be long - in the case of the large scale ITER project, decades! Even the small scale Lockheed Martin prototype could take another five to ten years. So a potential risk might be one of timing: a realistic fusion solution might take longer to develop than the time-frame of the XPRIZE.
Equally, excluding a potentially promising fusion solution because of the above timing aspect might mean that an alternative energy source is backed, which could be superseded by fusion power in later years (decades); effectively making the prize winning technology redundant.
Positive energy tests to evaluate this technology
The inputs and outputs for any energy generation process can be represented as shown in the System Representation. The efficiency of the system is represented by the output energy divided by the input energy. Note that all energy inputs should be accounted for. The input energy consists of the potential energy of the nuclear fuel, and the input energy required to raise the temperature and start the fusion reaction. For a plasma reaction vessel this thermal input energy might be required once (followed by a self-sustaining reaction); but a fuel pellet system might require an input of thermal energy for each pellet. The output of current systems is as heat; and later experiments will be required to demonstrate and quantify the process and efficiency for harnessing that heat and producing electrical power.
It might be quite cumbersome to test inventions in this area, since they tend to be sizeable, complex systems with significant energy inputs. A high degree of expertise would be needed if independent testing were envisaged. If the fusion energy gain factor Q were sufficiently high, say >10, evaluating the technology would become more straightforward.
- To measure temperature and density of the plasma light or X-rays can be used.
- An electrode in the plasma can be used to measure plasma density, potential and temperature.
- Geiger counters record the rate of neutron production from the nuclear reaction.
- Observation of the emitted electromagnetic spectrum reveals the plasma temperature.
The endurance of the first wall of the fusion reactor will decide research availability and lifespan of the first International Thermonuclear Research Reactor (ITER). Materials erosion, redeposition and mixing in the reactor are the critical processes responsible for modification of material properties under plasma impact. A research thesis presents several diagnostic techniques and their applications for studies of materials transport in fusion devices. 
Various plasma diagnostics used for the study of plasma characteristics in different plasma experiments ranging from low temperature to high energy density plasma are discussed in this publication on arXiv. 
Two different methods were used to determine the plasma temperature in a laser initiated fusion experiment .
- ITER - the international demonstrator project for high temperature nuclear fusion power
- Video introducing the concept of nuclear fusion power.
- Fusion energy: Frequently Asked Questions
- Plasma Confinement by Magnetic Fields
- Plasma Confinement
- Science Action: How does a magnetic field confine a plasma?
- Plasma (physics)
- Bostock A. (2017). System Representation, Energy Wiki
- Sandia National Laboratories Z-Machine
- Fusion (using the Z-machine)
- http://www.euroscientist.com/how-particle-physics-is-eroding-the-scientific-method/ Alexander Unzicker and Sheilla Jones
- In Theory: Is theoretical physics in crisis?
- Membership of the Natural Philosophy Society
- "Science" on Natural Philosophy Society
- Deuterium: a precious gift from the Big Bang
- Bostock A. (2017). Sustainability Scale, Innovation Future Specialist, (UK).
- Does fusion give off radiation? EURO Fusion: European Consortium for the Development of Fusion Energy
- Slovic and Weber (2013). Perception of Risk Posed by Extreme Events, Regulation of Toxic Substances and Hazardous Waste (2nd edition) (Applegate, Gabba, Laitos, and Sachs, Editors), Foundation Press, Forthcoming
- Michael Siegrist, Heinz Gutscher & Timothy C. Earle (2006). Perception of risk: the influence of general trust, and general confidence, Journal of Risk Research: Volume 8, 2005 - Issue 2
- Linda Steg and Inge Sievers (2016). Cultural Theory and Individual Perceptions of Environmental Risks, Environment and Behavior: Vol 32, Issue 2, pp. 250 - 269, First published date: July-26-2016
- List of fusion experiments
- Fusion Power
- Plasma Diagnostics
- Igor Bykov (2014), Doctoral Thesis in Physical Electro-technology: Experimental studies of materials migration in magnetic confinement fusion devices
- Rai, Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore BASIC CONCEPT IN PLASMA DIAGNOSTICS on arXiv.org
- Bang, Barbui et al, Temperature measurements of fusion plasmas produced by petawatt laser-irradiated D2-3 He or CD4-3 He clustering gases