In 1968, Coppi attended the third IAEA International Conference on Plasma Physics and Controlled Nuclear Fusion Research at Novosibirsk.

At this conference, Soviet scientists announced that they had achieved electron temperatures of over 1000 eV in a tokamak device (T-3).

He immediately collaborated with engineers at the Francis Bitter Magnet Laboratory, led by Bruce Montgomery, to design a compact (0.54 m major radius), high-field (10 T on axis) tokamak which he titled Alcator.

Alcator A was powered by the Bitter Laboratory's 32 MW DC motor-generators and was the first tokamak in the world to use an air-core transformer for ohmic current drive and heating.

ERDA was, however, enthusiastic about building another Alcator, and a solution was found: a 225 MVA alternator was donated to MIT by Con Ed from a plant on the East River in New York City.

The alternator arrived from Con Ed in early 1978 (its transport was complicated by the blizzard of 1978) and was incorporated into the system in the summer of 1978.

While Alcator C did not originally have the energy confinement time expected, due to the onset of ion temperature gradient turbulence at high values of

, pellet fueling was used to produce peaked density profiles and values of the nτ product of over 0.8 × 1020 s·m−3 were achieved in 1983.

This design was never formally proposed to the Department of Energy (DOE), but continued to evolve under Coppi's direction, eventually becoming the Italian–Russian IGNITOR device planned for construction at TRINITY near Troitsk, Russia.

At that time, the budget for magnetic fusion energy research in the United States had been increasing year-over-year, reaching a peak of $468.4 million in fiscal 1984.

That year, the PSFC was notified that for a time, budgets would be falling, and DOE policy would be to only fund upgrades to existing devices, not new machines.

The source frequency is 80 MHz and the standard minority heating scenarios are D(H) for 4.4–6.9 T and D(3He) for high field operation (7.3–8.0 T).

Phase contrast imaging (PCI) can be used to measure the mode converted waves directly in the plasma.

Power is provided by 250 kW klystron microwave amplifiers manufactured by CPI, Inc. Non-inductive operation for up to 0.5 s pulses at 500 kA was achieved.

Lower hybrid waves are launched preferentially in the direction opposite the plasma current (i.e. in the direction of electron travel) and deposit energy on electrons moving at approximately three times the thermal velocity via Landau damping.

[4][5] In 2016 Alcator C-Mod set a world record for plasma pressure in a magnetically confined fusion device, reaching 2.05 atmospheres – a 15 percent jump over the previous record of 1.77 atmospheres (also held by Alcator C-Mod).

This record plasma had a temperature of 35 million degrees C, lasted for 2 seconds, and yielded 600 trillion fusion reactions.

[7] Following completion of operations at the end of September 2016, the facility has been placed into safe shutdown, with no additional experiments planned at this time.

There is a wealth of data archived from the more than 20 years of operations, and the experimental and theoretical teams continue to analyze the results and publish them in the scientific literature.

ITER is not expected to be fully operational until 2034[9], meaning that Alcator C-Mod's record will hold for more than 15 years unless another new device is constructed before then.