6) Long pulses: a speciality of Tore Supra (p  1 - 2 )

Tore Supra, the only large machine in the world fitted with supra-conducting magnets, providing a permanent toroidal magnetic field, has become the champion of the study of long pulses, taking a step at a time towards steady state, indispensable for the reactor.

Indeed, the time scales of the different physical phenomena at stake in a fusion machine are very varied, going from less than a millisecond for the stability of magnetic equilibrium (MHD) to a matter of minutes for plasma-wall equilibrium and even hours for erosion  

A machine like Tore Supra, enabling exploration of long pulses of several minutes, is thus complementary to a machine like JET , very effective, but limited to a pulse duration of a few seconds.

It may be seen on the diagram opposite, where we have represented the characteristics of most of the present machines in terms of fusion performance (the triple product density/ confinement time/temperature of the Lawson criterion) as a function of  the discharge duration. Full in symbols represent performances already attained, empty symbols show expected performances for machines at project stage (like the next step of ITER) or improvements on existing machines (like Tore Supra with the CIMES project of extending its heating system).

JET is not far off expected fusion performances for the next step of ITER whereas Tore Supra (TS for the initiated) is getting closer to the required durations. Thus, while JET is galloping ahead like a racehorse, Tore Supra is continuing its endurance work and is just as indispensable.

 

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