Fusion plasma in a Tokamak is heated using High Power Radio Frequency (RF) waves. These RF waves are transmitted by an antenna in the doughnut-shaped vacuum chamber of the Tokamak, and they heat the plasma fuel and drive its current around the toroidal interior.

The RF waves are used to improve heating and current drive predictions for fusion plasmas. The development of a High-Power Amplifier (HPA) of 120 kW, operating over the 36 to 60 MHz range, has been successfully achieved at the Institute for Plasma Research (IPR).

The heating of the plasma in a Tokamak is crucial for achieving the high temperatures required for fusion reactions to occur. The temperatures inside the ITER Tokamak, for example, need to reach 150 million degrees Celsius, or ten times the temperature at the core of the Sun.

To achieve these extreme temperatures, the ITER Tokamak relies on three sources of external heating: neutral beam injection, ion cyclotron resonance heating (ICRH), and high-frequency electromagnetic waves.

A High-Power Amplifier (HPA) of 120 kW, operating over the 36 to 60 MHz range, has been successfully developed indigenously at IPR. This HPA is composed of indigenously fabricated High-Power RF Cavity and an imported Tetrode. All ancillaries such as 10 kW solid state power amplifier, high voltage power supply, auxiliary power supplies, and control systems are also fully indigenous. Characterization of the HPA has been completed up to the 40 MHz range and further tests are in progress. On successful completion of full characterization, including reliability, repeatability, and compliance with electro-magnetic standards, this cavity will be delivered to ITER as an in-kind contribution.

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