David Johnson and Charles Skinner, principal research physicists at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), have been appointed to three-year terms as ITER Scientist Fellows. They will join a network of internationally recognized researchers who will consult with ITER, the international fusion experiment under construction in France, on plans and components for the project, which is designed to demonstrate the practicality of fusion energy.
ITER is a large international fusion experiment aimed at demonstrating the scientific and technological feasibility of fusion energy.
ITER (Latin for "the way") will play a critical role advancing the worldwide availability of energy from fusion — the power source of the sun and the stars.
To produce practical amounts of fusion power on earth, heavy forms of hydrogen are joined together at high temperature with an accompanying production of heat energy. The fuel must be held at a temperature of over 100 million degrees Celsius. At these high temperatures, the electrons are detached from the nuclei of the atoms, in a state of matter called plasma.
Throughout 2017 researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have produced new insights into the science of fusion energy that powers the sun and stars and the physics of plasma, the hot, charged state of matter that consists of electrons and atomic nuclei, or ions, and makes up 99 percent of the visible universe. The research advances the development of fusion as a safe, clean and plentiful source of power, produced in doughnut-shaped facilities called tokamaks, and explores the diverse aspects and applications of plasma.
New insights into the science of fusion energy and the physics of plasma from researchers at PPPL.
Before scientists can effectively capture and deploy fusion energy, they must learn to predict major disruptions that can halt fusion reactions and damage the walls of doughnut-shaped fusion devices called tokamaks. Timely prediction of disruptions, the sudden loss of control of the hot, charged plasma that fuels the reactions, will be vital to triggering steps to avoid or mitigate such large-scale events.
Deep learning — a newer and more powerful version of modern machine-learning software — improves predictions of plasma disruptions.
A major challenge facing the development of fusion energy is maintaining the ultra-hot plasma that fuels fusion reactions in a steady state, or sustainable, form using superconducting magnetic coils to avoid the tremendous power requirement of copper coils. While superconductors can allow a fusion reactor to operate indefinitely, controlling the plasma with superconductors presents a challenge because engineering constraints limit how quickly such magnetic coils can adjust when compared to copper coils that do not have the same constraints.
International collaboration sets leading-edge example for controlling elongated plasma in superconducting devices such as ITER.
The arrival of six truckloads of electrical supplies at a warehouse for the international ITER fusion experiment on Oct. 2 brings to a successful conclusion a massive project that will provide 120 megawatts of power – enough to light up a small city − to the 445-acre ITER site in France.
A major issue facing ITER, the international tokamak under construction in France that will be the first magnetic fusion device to produce net energy, is whether the crucial divertor plates that will exhaust waste heat from the device can withstand the high heat flux, or load, that will strike them. Alarming projections extrapolated from existing tokamaks suggest that the heat flux could be so narrow and concentrated as to damage the tungsten divertor plates in the seven-story, 23,000 ton tokamak and require frequent and costly repairs.
Detailed computer simulation indicates good news for the international tokamak under construction in France.
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