DIII-D (fusion reactor)
Encyclopedia
DIII-D is the name of a tokamak
machine developed in the 1980s by General Atomics
in San Diego, USA, as part of the ongoing effort to achieve magnetically confined fusion
. DIII-D pioneered new technology including the use of beams of neutral particles to penetrate the confinement field
of the device and heat the plasma within. It achieved several milestones including the highest plasma β
parameter ever achieved at the time (early 1980s) and the highest neutron flux (fusion rate) ever achieved at the time (early 1990s). DIII-D continues to be operated by General Atomics, focusing primarily on exploration of the advanced tokamak regime. Advanced tokamaks are characterized by operation at high plasma β through strong plasma shaping
, active control of various plasma instabilities, and achievement of current and pressure profiles that produce high performance. DIII-D is currently (2005) the third-largest operating shaped tokamak in the world (after JET
in the UK and JT-60U
in Japan).
Tokamak
A tokamak is a device using a magnetic field to confine a plasma in the shape of a torus . Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape...
machine developed in the 1980s by General Atomics
General Atomics
General Atomics is a nuclear physics and defense contractor headquartered in San Diego, California. General Atomics’ research into fission and fusion matured into competencies in related technologies, allowing the company to expand into other fields of research...
in San Diego, USA, as part of the ongoing effort to achieve magnetically confined fusion
Magnetic confinement fusion
Magnetic confinement fusion is an approach to generating fusion power that uses magnetic fields to confine the hot fusion fuel in the form of a plasma. Magnetic confinement is one of two major branches of fusion energy research, the other being inertial confinement fusion. The magnetic approach is...
. DIII-D pioneered new technology including the use of beams of neutral particles to penetrate the confinement field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
of the device and heat the plasma within. It achieved several milestones including the highest plasma β
Beta (plasma physics)
The beta of a plasma, symbolized by β, is the ratio of the plasma pressure to the magnetic pressure...
parameter ever achieved at the time (early 1980s) and the highest neutron flux (fusion rate) ever achieved at the time (early 1990s). DIII-D continues to be operated by General Atomics, focusing primarily on exploration of the advanced tokamak regime. Advanced tokamaks are characterized by operation at high plasma β through strong plasma shaping
Plasma shaping
Magnetically confined fusion plasmas such as those generated in tokamaks and stellarators are characterized by a typical shape. Plasma shaping is the study of the plasma shape in such devices, and is particularly important for next step fusion devices such as ITER. This shape is conditioning partly...
, active control of various plasma instabilities, and achievement of current and pressure profiles that produce high performance. DIII-D is currently (2005) the third-largest operating shaped tokamak in the world (after JET
Joint European Torus
JET, the Joint European Torus, is the largest magnetic confinement plasma physics experiment worldwide currently in operation. Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and :DEMO....
in the UK and JT-60U
JT-60
JT-60 is the flagship of Japan's magnetic fusion program, previously run by the Japan Atomic Energy Research Institute and currently run by the Japan Atomic Energy Agency's Naka Fusion Institute in Ibaraki Prefecture, Japan...
in Japan).