A flux surface average for a tokamak is a way to measure the average magnetic field strength and shape within a tokamak reactor. It takes into account the variation of the magnetic field along the toroidal (donut-shaped) direction, as well as the poloidal (vertical) direction.
The flux surface average is calculated by dividing the total magnetic flux within the tokamak by the area of the flux surface. This gives an average value of the magnetic field strength within the tokamak at a particular radial distance from the center.
Flux surface average is an important parameter in tokamak design because it affects the stability and efficiency of plasma confinement. A higher flux surface average leads to better plasma confinement and a more stable reactor.
During plasma operation, the flux surface average can change due to variations in plasma density and temperature, as well as changes in the magnetic field strength. These changes can affect the stability and performance of the tokamak reactor.
Yes, the flux surface average can be controlled to some extent by adjusting the magnetic field strength and shape within the tokamak. However, other factors such as plasma density and temperature also play a role in determining the flux surface average.