Ion Cyclotron Heating

Ion cyclotron heating (ICH) is a technique used in fusion tokamaks to heat ions in a plasma by applying radio frequency (RF) waves. The RF waves used in ICH are typically in the range of tens to hundreds of megahertz.

To implement ICH in a fusion tokamak, an antenna system is used to couple the RF waves to the plasma. The waves create an oscillating electric field that interacts with the ions in the plasma. As the ions move in the presence of this electric field, they gain energy through a process called resonant absorption.

Resonant absorption occurs when the frequency of the RF waves matches the cyclotron frequency of the ions. The cyclotron frequency is the frequency at which ions in a magnetic field undergo circular motion. When the RF waves and the ions' cyclotron frequency are in resonance, the ions absorb energy from the waves more efficiently.

The resonant absorption process leads to the heating of the ions in the plasma. The absorbed energy increases the kinetic energy of the ions, causing them to move faster and collide with other particles in the plasma. These collisions transfer energy to the surrounding particles, resulting in an overall increase in plasma temperature.

ICH is an important technique in fusion tokamaks and is used to control and manipulate the properties of plasmas by selectively heating specific ions or regions within the plasma.

In summary, ion cyclotron heating is a method of heating ions in a fusion tokamak by applying RF waves that are in resonance with the ions' cyclotron frequency. This resonant absorption process efficiently transfers energy from the waves to the ions, leading to their heating and increasing the overall plasma temperature.