Interpretation of the I-Regime and transport associated with relevant heavy particle modes

The excitation of a novel kind of heavy particle [B. Coppi et al., Phys. Rev. Lett. 17, 377 (1966); B. Coppi and T. Zhou, MIT(LNS) Report HEP 09/04, 2009, Cambridge, MA [Phys. Lett. A 375, 2916 (2011)]] mode at the edge of the plasma column is considered as the signature of the I-confinement Regime [R. McDermott et al., Bull. Am. Phys. Soc. 53, 112 (2008); R. McDermott et al., Phys. Plasmas 16, 056103 (2009); E. Marmar et al., Bull. Am. Phys. Soc. 54, 97 (2009); D. Whyte et al., Nucl. Fusion 50, 105005 (2010); A. Hubbard et al., Phys. Plasmas 18, 056115 (2011)]. The outward transport of impurities produced by this mode is in fact consistent with the observed expulsion of them from the main body of the plasma column (a high degree of plasma purity is a necessary feature for fusion burning plasmas capable of approaching ignition). Moreover, the theoretically predicted mode phase velocity, in the direction of the electron diamagnetic velocity, has been confirmed by relevant experimental analyses [I. Cziegler, private communication (2010)] of the excited fluctuations (around 200 kHz). The plasma ''spontaneous rotation'' in the direction of the ion diamagnetic velocity is also consistent, according to the accretion theory [B. Coppi, Nucl. Fusion 42, 1 (2002)] of this phenomenon, with the direction of the mode phase velocity. Another feature of the mode that predicted by the theory is that the I-Regime exhibits a knee of the ion temperature at the edge of the plasma column, but not one of the particle density as the mode excitation factor is the relative main ion temperature gradient exceeding the local relative density gradient. The net plasma current density appearing in the saturation stage of the relevant instability, where the induced particle and energy fluxes are drastically reduced, is associated with the significant amplitudes of the poloidal magnetic field fluctuations [D. Whyte et al., Nucl. Fusion 50, 105005 (2010); A. Hubbard et al., Phys. Plasmas 18, 056115 (2011)] observed to accompany the density fluctuations. The theoretical implications of the significant electron temperature fluctuations [A. White, private communication (2011)] observed are discussed.