The WEGA fusion device, a member of the Wendelstein family at IPP, has been in operation since 1975 at various sites with intermittent interruptions.

Technical data and components of the WEGA device

WEGA with removed peripherie. Visible are the blue toroidal field coils and red insulated vertical magnetic coils

The vessel consists of a stainless steel torus with major radius 72 cm and minor radius 19 cm. 100 ports are available for pumping, gas feed, components for the microwave heating and the integration of various diagnostics.

Four different types of magnetic field coils allow for a highly flexible magnetic field configuration: 40 toroidal field coils create the main field, two helically wound coils in fivefold toroidal symmetry overlay the required drill of the fieldlines; two pairs of vertical field coils allow for a radial positioning of the plasma tube and an additional coil is available for creation or compensation of field asymmetries.

Stationary operation was possible at low currents/low magnetic fields; at fields B = 0.5 T a quasi stationary operation was possible for up to 15 seconds. The plasma minor radius strongly depends on the choosen magnetic field configuration. Its maximum value a = 11 cm resulted in a plasma volume of 0.16 m3. Working gas was Helium, Argon or Hydrogen.

Plasma heating was performed with microwaves at frequencies of 2.45 GHz and 28 GHz with maximum power of 26 kW and 10 kW respectively. This resulted in electron temperatures of 10 to 50 eV and ion temperatures between 1 and 5 eV. The plasma was not fully ionized, the obtained density was in the range of 1017 to 1018 m -3. The last investigations focused on the heating of so called overdense plasmas by microwaves which allow for densities larger than 1019 m -3.



 Technical data:

 Major plasma radius

0.7 metres
 Minor plasma radius 0.11 metres
 Magnetis field
0.5 tesla
 Number of coils
43 (+ helical winding)
 Plasma volume 0.16 cubic metres
 Pulse length 20 seconds
 Plasma heating 26 kilowatts
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