How to heat a plasma to 10^8 degrees Celsius

[psuedoben]

Recently, Germany broke headlines when they fired up their nuclear fusion reactor. As I'm sure most everyone on this forum knows this, they plan on creating fusion by heating plasma to absurd temperatures while containing it in a magnetic field. What method do they use to heat the gas and eventually the plasma to those temperatures?

 

[DrClaude]

From https://www.iter.org/mach/Tokamak

To start the process, air and impurities are first evacuated from the vacuum chamber. Next, the magnet systems that will help to confine and control the plasma are charged up and the gaseous fuel is introduced. As a powerful electrical current is run through the vessel, the gas breaks down electrically, becomes ionized (electrons are stripped from the nuclei) and forms a plasma.

As the plasma particles become energized and collide they also begin to heat up. Auxiliary heating methods help to bring the plasma to fusion temperatures (between 150 and 300 million °C). Particles "energized" to such a degree can overcome their natural electromagnetic repulsion on collision to fuse, releasing huge amounts of energy.

 

[Khashishi]

Wendelstein 7-X is not a tokamak, so it doesn't have a large toroidal current, so the above doesn't quite apply. W7-X is mainly heated by electron cyclotron resonance heating (ECRH) using millimeter scale electromagnetic waves from some antennas.

In stellarators and tokamaks, the standard ways of heating are:
*ohmic heating (another name for resistive heating due to the current in the plasma). This is always present in tokamaks but becomes less effective at high temperatures due to the low resistance of the plasma;
*neutral beam heating. A high energy particle beam is fired into the plasma through a side port and collides with the plasma particles
*ion cyclotron resonance heating (ICRH): antenna voltages are oscillated in synch with the cyclotron motion of heavy ions in the plasma. This generates EM waves that can be absorbed by the plasma.
*electron cyclotron resonance heating (ECRH or ECH): antenna voltages are oscillated in synch with the cyclotron motion of electrons in the plasma