Subscribe options

Select your newsletters:

Please enter your email address:

@

News & Media

Latest ITER Newsline

  • FEC2020 | Seeking sponsors for 28th IAEA Fusion Energy Conference

    For only the third time since 1961, the International Atomic Energy Agency's Fusion Energy Conference will be taking place in France—hosted jointly by the Frenc [...]

    Read more

  • Nuclear safety | Under constant scrutiny

    Because one of the elements involved in the fusion reaction is the radioactive isotope tritium, and because the hydrogen fusion reaction itself generates a high [...]

    Read more

  • Power conversion | Alien structures and strange contraptions

    There are places in ITER that seem to belong to another world, places full of alien structures and strange contraptions. The feeling—a mixture of awe and puzzle [...]

    Read more

  • Tokamak Complex | A changing landscape

    For the past three years, the view from the top of the highest worksite crane has not changed much. Inside of the Tokamak Complex, 80 metres below, concrete gal [...]

    Read more

  • Ion cyclotron heating | How to pump 20 MW of power into 1 gram of plasma

    To power the ion cyclotron system, the ITER Organization and its partners are designing not only new antennas, which will be housed in the tokamak vessel, but a [...]

    Read more

Of Interest

See archived entries

Last, record-setting plasma shot for MIT's Alcator C-Mod

On Friday, 30 September, scientists and engineers at MIT's Plasma Science and Fusion Center (PSFC) made a leap forward in the pursuit of clean energy by setting a new world record for plasma pressure on the Alcator C-Mod tokamak.

The world record was achieved on Alcator C-Mod's last day of planned operation. After 23 years of operation and approximately 33,000 plasma shots, the facility was officially closed in September. (Click to view larger version...)
The world record was achieved on Alcator C-Mod's last day of planned operation. After 23 years of operation and approximately 33,000 plasma shots, the facility was officially closed in September.
The results will be presented to the international fusion community by senior research scientist Earl Marmar at the IAEA Fusion Energy Conference that opens today in Kyoto, Japan.

Plasma pressure is one of the key ingredients to producing energy from nuclear fusion, which demands that the product of three factors (the so-called "triple product"—a plasma's particle density, its confinement time, and its temperature) reaches a certain value. Above this value the energy released in a reactor exceeds the energy required to keep the reaction going.

A time map of all pressures achieved since the start of operation. The record-setting plasmas and the recent high-performance campaign are apparent on the very top right of the graph. Source: PSFC (Click to view larger version...)
A time map of all pressures achieved since the start of operation. The record-setting plasmas and the recent high-performance campaign are apparent on the very top right of the graph. Source: PSFC
Pressure, which is the product of density and temperature, accounts for about two-thirds of the challenge. The amount of power produced increases with the square of the pressure, so doubling the pressure leads to a fourfold increase in energy production.

In the plasma pulse run on 30 September, MIT and guest scientists were able to achieve 2.05 atmospheres of pressure, passing the previous world record of 1.77 atmospheres that had been achieved in 2005 on the same device. This result—an improvement of 15 percent—was achieved in a 35-million-degree plasma that lasted two seconds.

This pressure record is likely to stand until the operation of ITER, which is expected to reach 2.6 atmospheres when in full operation.

In the plasma pulse run on 30 September, scientists were able to achieve 2.05 atmospheres of pressure in a 35-million-degree plasma that lasted two seconds. The graph above shows some of the shot's properties. Source: PSFC (Click to view larger version...)
In the plasma pulse run on 30 September, scientists were able to achieve 2.05 atmospheres of pressure in a 35-million-degree plasma that lasted two seconds. The graph above shows some of the shot's properties. Source: PSFC
Three different strategies for breaching the pressure record were tried by the engineers, technicians, scientists and students present in the control room. Two came very close to reproducing the previous mark, and the third set the ultimate record. Two of the approaches, including the record-setting one, were led by scientists from other laboratories in the US, including the Princeton Plasma Physics Laboratory, the Oak Ridge National Laboratory, and General Atomics in San Diego. Each approach was thoroughly planned before hand and attempted sequentially throughout the day.

"This is a remarkable achievement that highlights the highly successful Alcator C-Mod program at MIT," said Dale Meade, former deputy director at the Princeton Plasma Physics Laboratory. "The record plasma pressure validates the high-magnetic-field approach as an attractive path to practical fusion energy."

Alcator C-Mod is the world's only compact, high-magnetic-field fusion reactor of the tokamak variety. The device's high-intensity magnetic field—up to 8 tesla, or 160,000 times the Earth's magnetic field—allows the device to create the dense, hot plasmas and keep them stable at more than 80 million degrees. Its magnetic field is more than double what is typically used in other designs, which quadruples its ability to contain the plasma pressure.

C-Mod is third in the line of high-magnetic-field tokamaks to be built and operated at MIT. The result was achieved on Alcator C-Mod's last day of planned operation. The facility officially closed in September after 23 years of operation and approximately 33,000 plasmas.

Read the original report of the world record on the PSFC and MIT websites. 


return to the latest published articles