Assess the helicon heating and current drive efficiency with core absorption in L-mode plasmas
2024 Research Campaign, Heating and Current Drive
Purpose of Experiment
In order to keep the hot plasma confined within the fusion reactor, a tokamak uses nested magnetic field lines that spiral around doughnut-shaped surfaces. The twist in the magnetic field lines comes from an electrical current that is created in the plasma. One way to generate this current is by injecting electromagnetic waves into the plasma. Just like a microwave oven can be used to heat food with electromagnetic waves with frequencies that are chosen to match the vibrations of water molecules and drive them like a tuning fork, electromagnetic waves can transfer energy and momentum to the plasma by matching the natural motion of the electrons, which carry the current in the plasma. The purpose of this experiment is to demonstrate that a specific type of electromagnetic wave, called helicon waves, can generate a current in the plasma, which has been predicted theoretically but never before measured in a fusion experiment. If successful, helicon waves will provide a new method for sustaining the plasma current in a future commercial fusion power plant that may be more efficient than other possible techniques, potentially reducing the amount of input energy needed to generate the same amount of fusion power.