Stability and quench propagation velocities measurements an the 'racetrack' mockup of ATLAS toroid coil

A mock-up of ATLAS toroid coil, which is one df the 3 detectors presently u nder construction for the future Large Hadron Collider at CERN, had been te sted at Saclay, Various experiments have been led to check the validity of, important technical options for the magnet. This paper focuses on thermal s tability and quench propagation velocities measurements. For a 70x7 mm(2) a lwuminum-stabilized conductor carrying a 20 kA current, a 4-5 joule minimum quench energy and a 20 m/s longitudinal quench propagation velocity were f ound. We also studied the dependence of those features according to the ope rating current in the 5-20kA range.