Dr. L. Bühler

Magnetohydrodynamic Experiments in NaK Karlsruhe

Objectives: Magnetohydrodynamic (MHD) research performed in the experimental facility MEKKA aims to investigate liquid metal flows relevant for fusion applications, where the magnetic field that confines the plasma is very strong.

Short description: The MEKKA-facility (Figs.1, 2) consists of a large Na22K78 liquid metal loop and two magnets. The entire NaK loop with the test section can be moved on rails along the axis of each magnet. This allows a good access to the instrumented test section and variable positioning of the experiment within the magnets. This facility is capable of attaining MHD-parameters relevant for liquid-metal fusion blankets (Interaction parameters in the range of N=102-105, Hartmann numbers up to Ha=104).


Magnet types super conducting normal conducting
Magnet gap shape cylindrical cuboid
Space of homogeneous field (mm) L=450, D=400 L=800, H=165, W=483
max. field strength /Tesla/ 3.6 2.2


Liquid loop  
NaK inventory 200 l
Electromagnetic pump
  • used for high temperature wetting
  • suitable for moderate flow rates
Mechanical centrifugal pump
  • maximum flow rate: 25 m3/h
  • maximum pressure head: 9 bar
  • operational T<150°C


Sketch of MEKKA Loops MEKKA-Labor

MEKKA loop