User:Mountainlife00/general fusion

General Fusion is a Canadian company based in Burnaby, British Columbia, which was created for the development of fusion power based on magnetized target fusion (MTF). It was founded in 2002 by physicist Dr. Michel Laberge with the goal of developing a commercially viable fusion power plant. General Fusion has since developed its plasma injector and compression technology, and is integrating these components into a prototype machine. It is a private fusion company funded by a variety of investors, including Chrysalix venture capital, the Business Development Bank of Canada—a Canadian Crown corporation, Bezos Expeditions, Cenovus Energy, GrowthWorks Capital, Khazanah Nasional—a Malaysian sovereign wealth fund, and Sustainable Development Technology Canada.

Organization
As of 2016, General Fusion has 65 employees and has raised over CA$100 million in funding from a global syndicate of investors. The company was founded in 2002 by former Creo Products senior physicist and principal engineer Dr. Michel Laberge, who completed his Ph.D in fusion physics at the University of British Columbia in 1990.

The company is overseen by a board of directors chaired by Frederick W. Buckman Sr., former CEO of Consumers Power. Advising the board is a Scientific Advisory Committee, which includes Carol M. Browner, physicist T. Kenneth Fowler , and former astronaut Mark Kelly.

Power Plant Design
General Fusion’s Magnetized Target Fusion system uses a ~3 meter sphere filled with a liquid mixture of lead and lithium. The liquid is spun to open up a vertical cylindrical cavity in the centre of the sphere (vortex). This vortex flow is established and maintained by an external pumping system; the liquid flows into the sphere through tangentially directed ports at the equator and is pumped out radially through ports near the poles of the sphere.

Attached to the top of the sphere is a plasma injector, from which a pulse of magnetically-confined deuterium-tritium plasma fuel is injected into the center of the vortex. A few milligrams of gas are used per pulse, and the gas is ionized by a bank of capacitors to form a spheromak plasma (self confined magnetized plasma rings) composed of the deuterium-tritium fuel. The company has demonstrated plasma lifetimes up to 2 milliseconds and electron temperatures in excess of 400 eV.

The outside of the sphere is covered with pistons, which simultaneously impact a set of stationary anvils on the surface of the sphere to create acoustic pressure waves in the liquid metal. The pressure waves converge to become a spherical shockwave at the center of the sphere, causing the liquid metal vortex to collapse and compress the plasma. The compression increases the temperature of the plasma to the point where the deuterium and tritium nuclei fuse, releasing energy in the form of fast neutrons.

This energy heats up the liquid metal, which is then pumped through a heat exchanger and used to generate electricity via a steam turbine. The plasma formation and compression process repeats and the liquid metal is continuously pumped through the system. Some of the steam is recycled to power the pistons.

In addition to its role in compressing the plasma, the use of a liquid metal liner provides a way of shielding the power plant structure from neutrons released by the deuterium-tritium fusion reaction, overcoming the problem of structural damage to plasma-facing materials. The use of liquid lithium in the mixture enables the breeding of tritium fuel, while the liquid metal provides a means of extracting the energy from the system via a heat exchanger.

LINUS
General Fusion's approach is based on the LINUS concept developed by the United States Naval Research Laboratory (NRL) beginning in 1972. Researchers at NRL suggested an approach that retains many of the advantages of liner compression to achieve small, high-energy-density fusion, while using a liquid metal as the liner to avoid the major draw back of replacing hardware.

In the LINUS concept, a rotating liquid lithium liner is imploded mechanically, using high pressure helium as the energy source. The liner acts as a cylindrical piston to compress a magnetically-confined plasma adiabatically to fusion temperature and relatively high density (~1017 ions.cm-3). In the subsequent expansion the plasma energy and the fusion energy carried by trapped alpha particles is directly recovered, making the mechanical cycle self-sustaining.The LINUS reactor can thus be regarded as a fusion engine, except that there is no shaft output: all the energy appears as heat.

The liquid metal acts as both a compression mechanism and heat transfer mechanism, allowing the energy from the fusion reaction to be captured as heat. LINUS researchers anticipated that the liner could also be used to breed tritium fuel for the power plant, and would protect the machine from high-energy neutrons by acting as a regenerative first wall.

Synchronizing the timing of the compression system was not possible with the technology of the time, and the proposed design was never constructed. General Fusion's Chief Scientist, Dr. Michel Laberge, has stated that these timing limitations can now be overcome with the use of modern electronics.

Science
To further the development of its MTF power plant, General Fusion is conducting experiments in plasma target development and magnetic compression. The company regularly publishes theoretical and experimental results in peer review journals and presents at international scientific conferences. General Fusion has a research library on their website.

Magnetized Target Fusion
General Fusion is pursuing an approach to fusion broadly called magnetized target fusion (MTF), also called Magneto Inertial Fusion. MTF combines features of magnetic confinement fusion (MCF) and inertial confinement fusion (ICF). In the MTF approach, a plasma (commonly a compact toroid) is confined in a magnetic field and then compressed. The compression increases density and temperature and boosts the magnetic field, lengthening confinement time. During compression the plasma undergoes adiabatic heating, increasing the temperature to the conditions required for fusion.

While MTF systems can use a variety of compression drivers, General Fusion is developing acoustically driven magnetized target fusion, using pistons driven by compressed gas to compress the plasma within a conductive metal liner.

Compact Toroid Plasma
The plasma injector devices form a self-organizing spheromak-configuration plasma, containing embedded toroidal and poloidal magnetic fields and corresponding plasma currents.

Magnetic Compression
Image currents in the wall

Research and Development
The company has developed the sub-systems of the power plant, including plasma injectors and compression driver technology. Patents have been awarded for a fusion energy reactor design, as well as enabling technologies such as plasma accelerators , methods for creating liquid metal vortexes , and lithium evaporators.

Plasma Injectors
Plasma injectors provide the fuel supply for the MTF power plant, injecting a deuterium-tritium plasma into the compression chamber.

Compact toroid plasmas are formed by a coaxial Marshal gun (a type of plasma railgun), with magnetic fields supported by internal plasma currents and eddy currents in the flux conserver wall. The company has constructed and operated more than a dozen plasma injectors, iterating designs to improve the performance of the plasma. These include large two-stage injectors with formation and magnetic acceleration sections (dubbed "PI" experiments), and three generations of smaller, single-stage formation-only injectors (MRT, PROSPECTOR and SPECTOR). In 2016 the company published research demonstrating spheromak plasma lifespans of up to 2 milliseconds and temperatures in excess of 400 eV on its SPECTOR generation of injectors.

Compression Driver Technology
Pneumatic pistons are used to create a converging spherical wave that compresses the plasma. Each system consists of a 100 kg, 30 cm diameter hammer piston driven down a 1 m long bore by compressed air. The hammer piston strikes an anvil at the end of the bore, generating a large amplitude acoustic pulse that is transmitted to the liquid metal in the compression chamber via the piston anvil. To create a spherical wave, the timing of these strikes must be controlled to within 10 µs of each other. The company has recorded sequences of consecutive shots with impact velocities of 50 m/s and timing synchronization within 2 µs.

A proof-of-concept prototype compression system was constructed in 2013 with 14 full size pistons around 1 meter diameter spherical compression chamber to demonstrate pneumatic compression and collapse of a liquid metal vortex.

Liquid Metal Systems
The proof-of-concept prototype compression system incorporates technology for forming a vortex of liquid metal as would be required in an MTF power plant. This consists of a 15 tonne liquid lead reservoir, pumped at 100 kg/s to form a vortex inside a 1 meter diameter spherical compression chamber.

Funding
As of late 2016, General Fusion had received over $100 million in funding from a global syndicate of investors and the Canadian Government’s Sustainable Development Technology Canada (SDTC) fund.

Chrysalix Energy Venture Capital, a Vancouver-based venture capital firm, led a C$1.2 million seed round of financing for General Fusion in 2007. As of 2016 General Fusion remained in Chrysalix' portfolio. Other Canadian venture capital firms that participated in the seed round were GrowthWorks Capital and BDC Venture Capital.

In 2009 a consortium led by General Fusion was awarded C$13.9 million by Sustainable Development Technology Canada (SDTC) to conduct a four-year research project on "Acoustically Driven Magnetized Target Fusion". SDTC is a foundation established by the Canadian government. The other member of the consortium is Los Alamos National Laboratory.

A 2011 Series B round raised $19.5 million from a syndicate including Bezos Expeditions, Braemar Energy Ventures, Business Development Bank of Canada, Cenovus Energy, Chrysalix Venture Capital, Entrepreneurs Fund, and GrowthWorks Capital.

In May 2015 the government of Malaysia’s sovereign wealth fund, Khazanah Nasional Berhad, led a $27 million funding round.

SDTC awarded General Fusion a further C$12.75 in March 2016 to for the project “Demonstration of fusion energy technology” in a consortium with McGill University (Shock Wave Physics Group) and Hatch Ltd.

Research Collaborations

 * Microsoft: In May 2017 General Fusion and Microsoft announced a collaboration to develop a data science platform based on Microsoft's Azure cloud computing system. A second phase of the project will apply machine learning to the data, with the goal of discovering new insights into the behavior of high temperature plasmas.
 * Los Alamos National Laboratory: Cooperative research and development agreement for magnetized target fusion research.
 * McGill University: Development of techniques to understand the behavior of the metal wall (liner) during compression and how it may affect the plasma
 * Princeton Plasma Physics Laboratory: MHD simulation of compression during MTF experiments
 * Queen Mary University of London: High fidelity simulations of non-linear sound propagation in multiphase media of nuclear fusion reactor
 * Hatch Ltd: Front end engineering and design for a fusion energy demonstration system

Crowdsourcing
Beginning in 2015, the company conducted three crowdsourcing challenges through Waltham, Massachusetts-based firm Innocentive.

The first challenge was Method for Sealing Anvil Under Repetitive Impacts Against Molten Metal. General Fusion successfully sourced a solution for “robust seal technology” capable of withstanding extreme temperatures and repetitive hammering, so as to isolate the rams from the liquid metal that fills the sphere. The company awarded Kirby Meacham, an MIT-trained mechanical engineer from Cleveland, Ohio, the $20,000 prize.

A second challenge, Data-Driven Prediction of Plasma Performance, began in December 2015 with the aim of identifying patterns in the company’s experimental data that would allow it to further improve the performance of its plasma.

The third challenge ran in March 2016, seeking a method to quickly and reliably induce a substantial current to jump a 5-10 cm gap within a few hundred microseconds, and was titled “Fast Current Switch in Plasma Device”. A prize of $5,000 was awarded to a post-doctoral researcher at Notre Dame, Indiana.