Wendelstein 7-X

• Prove the success of the stellarator optimisation concept: Improved particle and energy confinement and stable plasma equilibrium under conditions like those in a power plant
  
• Operation at maximum plasma pressure and beta values (plasma pressure relative to the counter pressure from the magnetic field)  of 4 to 5 percent, as required for a reactor
  
• Application of effective non-ohmic heating methods to produce and heat the plasma under steady state conditions
  
• Investigation of the impurity transport and development of methods of impurity control
  
• Long-time and quasi-stationary operation for all device components
  
• Control of plasma-wall interaction, particle recycling and refuelling under the conditions of continuous operation by means of a divertor at the plasma boundary
  

These objectives can be reached by an optimised magnetic field as realised in W7-X by a set of superconducting modular magnetic coils. The animation below illustrates the three-dimensionality and symmetry of the W7-X magnetic field coils and the stellarator plasma, for example the plasma cross section varying from bean to triangular shape.

Click to start animation (.mpg 150 MB)