FTU is a compact high magnetic field device aimed at studying high density plasmas in conditions close to those foreseen on ITER. An internal transport barrier lasting several confinement times has been obtained in 5.5 T/0.5 MA discharges with LHCD plus off-axis ECRH on the current ramp. Central temperatures of about 11 keV were achieved at ITER like central density values. Radiative improved mode studies show an increase in the energy confinement time following Ne injection with the radiated fraction reaching 90%. Operation with full LHCD at high density and current have been obtained with the LH system working close to the nominal performance. Steady and modulated ECRH transport studies confirm previous findings that the electron temperature profile is stiff if the magnetic shear is finite. High performance, steady PEP modes have been extensively studied. Careful timing of the pellet sequence allowed a high degree of reproducibility. Synergy studies with LH and EC waves injection have been performed both in the upshifted and downshifted scheme in which the EC waves are absorbed by the LHCD generated fast electrons, showing an increase in the current drive efficiency.
Overview of the FTU results
A Bruschi;L Carraro;S Cirant;F Gandini;G Granucci;E Lazzaro;S Nowak;ME Puiatti;P Scarin;A Simonetto;C Sozzi;M Valisa;
2003
Abstract
FTU is a compact high magnetic field device aimed at studying high density plasmas in conditions close to those foreseen on ITER. An internal transport barrier lasting several confinement times has been obtained in 5.5 T/0.5 MA discharges with LHCD plus off-axis ECRH on the current ramp. Central temperatures of about 11 keV were achieved at ITER like central density values. Radiative improved mode studies show an increase in the energy confinement time following Ne injection with the radiated fraction reaching 90%. Operation with full LHCD at high density and current have been obtained with the LH system working close to the nominal performance. Steady and modulated ECRH transport studies confirm previous findings that the electron temperature profile is stiff if the magnetic shear is finite. High performance, steady PEP modes have been extensively studied. Careful timing of the pellet sequence allowed a high degree of reproducibility. Synergy studies with LH and EC waves injection have been performed both in the upshifted and downshifted scheme in which the EC waves are absorbed by the LHCD generated fast electrons, showing an increase in the current drive efficiency.File | Dimensione | Formato | |
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