Tore Supra is proposed to play a new role in the ongoing experimental search for axions in our galaxy's dark matter halo.
The axion (postulated as hypothetical elementary particle arising from the Peccei-Quinn solution to the strong CP problem) is a good dark matter candidate, and it can be detected by an ultra-sensitive and low-noise microwave receiver in a resonant cavity with a large axial magnetic field. Axions convert in a magnetic field into photons, generating a tiny amount of radio frequency power.
The tokamak's large and strong magnetic field stimulates axions that enter the cavity to convert into single microwave photons. The conversion is resonantly enhanced when the cavity resonant frequency is near the axion rest mass energy. Or, as physicists say, it "uses the axion-electromagnetic coupling to induce resonant conversion of axions to photons". The power from axion-to-photon conversion on resonance depends on the volume of the cavity and the square of the product of the transverse magnetic field component and its length, making tokamaks a good candidate to be used as detection apparatus.
Similar to the axion, such experiment at Tore Supra could be used to look for the "chameleon", another a postulated particle (with our sun as a postulated source) that could be responsible for dark energy. When coupled to ESA's X-ray telescope, the biggest scientific satellite ever built in Europe, we could be looking at chameleons originating from the sun and channel them to the detectors inside Tore Supra.
Microwave cavity searches for axions and chameleon scalars have been attempted with the CAST detector of CERN and at the Axion Dark Matter eXperiment of the University of Washington, but none have been been successful in detecing one of these exotic particles so far. Tore Supra would be more powerful in detection capability than both these machines.
If the strategic plan for these experiments will be approved in July, Tore Supra can expected to be made available to search for the dark matter particles for a maximum of 3 months in the coming two years.