S. Coda, 46 th APS-DPP meeting, Savannah, 19 Nov S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 S. Coda, MHD workshop, PPPL, 22 Nov Steady-state, fully bootstrap-sustained discharges in the TCV tokamak with O. Sauter, M.A. Henderson, T.P. Goodman and the TCV team Centre de Recherches en Physique des Plasmas EPFL, Association Euratom-Fédération Suisse, Lausanne, Switzerland S. Coda

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 The steady-state tokamak inductive operation is always pulsed  inherently limiting for a reactor “advanced tokamak” alternative:  external non-inductive current drive (difficult!)  tailor current profiles to create low-transport core (possibly transport barrier)  steep gradients  high bootstrap

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Bootstrap alignment necessary for high bootstrap fractionnecessary for high bootstrap fraction appears good (several AT experiments) can do away with external current drive altogether? need exact alignment p j bs j  =0  =1

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007  =0  =1 can do away with external current drive altogether? need exact alignment and stable equilibrium Bootstrap alignment p j bs j

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007  =0  =1 Bootstrap alignment p j bs j steady state = stable aligned state

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 TCV R = 0.88 m, a = 0.25 m I p < 1 MA, B T < 1.54 T 3.0 MW X2 ECRH power, 6 steerable launchers

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July % bootstrap with balanced co- and counter-ECCD Beams matched locally for zero nominal ECCD Pre-existing steady-state reversed shear and eITB

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July % bootstrap with balanced co- and counter-ECCD non-inductive no net ECCD bootstrap overdrive

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July % bootstrap without ECCD: ramp-up eITB evolves to steady state

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Equilibrium state: narrow barrier H factor ~4-6 H factor ~2.5-3

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Equilibrium state: negative central shear

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Steady state found at different powers

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Spontaneous bootstrap overdrive Current ramp-up with no external sources

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 MHD survival: avoid I p <0 injection

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Conclusions and outlook achieved steady-state discharges with fully self-sustained plasma current stable and quiescent bootstrap current alignment requires a narrow ITB systematic exploration of parameter space (especially density, power) remains to be performed

Full bootstrap discharges in TCV S. Coda, 34 th EPS Conf. on Plasma Physics, Warsaw, 5 July 2007 Bootstrap current density j bs