MAST Upgrade generates first plasma

Start of operation for compact Tokamak in Culham, Great Britain

October 29, 2020

Today, the new MAST Upgrade fusion plant started operation at Culham Centre for Fusion Energy, UK, with its first plasma.

Technical drawing of MAST Upgrade, a spherical tokamak with three metres in diameter

MAST Upgrade is the result of a seven-year upgrade program for the “Mega Ampere Spherical Tokamak” MAST, which was in operation at Culham from 2000 to 2013. MAST was modified to achieve longer pulses, higher heating power and a stronger magnetic field, as well as to test a new particle exhaust system. MAST Upgrade, a tokamak with three metres in diameter, now has stronger magnets, additional instruments to observe and control the plasma, increased power of the particle heating devices and can generate plasma discharges up to five seconds duration.

MAST Upgrade is to explore the path to spherical tokamak power plants and examine whether a more compact design could allow for smaller and thus cheaper fusion power plants. With its thin central column, the almost spherical facility therefore differs significantly from tokamaks such as ASDEX Upgrade at Garching, the European joint experiment JET or the international ITER fusion experimental reactor, which are characterized by a wide central column and a ring-shaped plasma.

For particle exhaust, MAST Upgrade is equipped with a novel divertor. Magnetic coils stretch the plasma edge into exotic shapes such as an X or a multi-pronged snowflake. These give the plasma more time and space to radiate away its energy before it finally reaches the wall of the plasma vessel at the divertor plates – an effort to reduce the load on the divertor plates.

Fusion researchers throughout Europe followed the first plasma discharge via video. Congratulations to the MAST upgrade team came from Programme Manager Tony Donné on behalf of the European fusion research programme EUROfusion: “We are looking forward to the scientific results from this machine with its super-long divertor leg, which will give important guidance to ITER and DEMO”.

Also some IPP scientists are planning comparative experiments at the two different tokamaks ASDEX Upgrade in Garching and MAST Upgrade in Culham. Because of Corona, however, it will not be possible to travel to England soon. There are currently discussions about whether experiments can be carried out by remote control.

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